Solid State Laser News

[Grey Havoc]

Still Unhappy With Progress On Directed Energy Weapons, SWO Boss Wants More Land Based Testing To Speed Use On Ships - Defense Daily

Laser and high-powered microwave systems are key to increasing magazine depth aboard ships to defend themselves and other assets, but the technologies are

www.defensedaily.com

 

[Forest Green]

Wonder if particle beams would be more effective?

 

[bcredman]

Still Unhappy With Progress On Directed Energy Weapons, SWO Boss Wants More Land Based Testing To Speed Use On Ships - Defense Daily

Laser and high-powered microwave systems are key to increasing magazine depth aboard ships to defend themselves and other assets, but the technologies are

www.defensedaily.com

The article at the above link is behind a pay wall. Here is a link to a similar article that is free to view: https://defensescoop.com/2024/01/09/navy-swo-boss-frustrated-by-shortage-of-directed-energy-weapons/

 

[bcredman]

Wonder if particle beams would be more effective?

For what application/mission?

If your question is in response to the article Still Unhappy With Progress On Directed Energy Weapons..., the answer is No, particle beams would not be more effective than lasers or microwaves for the shipborne or land based air defense since particle beams cannot propagate very far in the atmosphere because of scattering. A possible way around the particle beam scattering in the atmosphere problem is to use a very high peak power pulsed laser to form a plasma channel that confines a charged particle beam to the plasma channel. This has been demonstrated with propagating electron beams in the atmosphere. However, the technology readiness level of such particle beam weapons is much lower than that of solid state laser and microwave weapons, so they would not solve the issue discussed in the article of the transition of laser weapons from R&D to operational fielding being too slow to meet the present need for air defense.

If your question is about the use of particle beams instead of lasers for clearing orbital debris by slowing down the debris so that it re-enters and burns up, my guess is perhaps if the particle beam system is deployed in orbit, but it would not work from ground to space as proposed for the laser system, unless the laser induced plasma channel technique discussed above is used to prevent the particle beam from being scattered by the atmosphere.

 

[Forest Green]

Has that technique ever been tried?

 

[bcredman]

Has that technique ever been tried?

See
https://www.sciencedirect.com/science/article/abs/pii/S0094576522004921#:~:text=Contactless space debris removal from the geostationary orbit protected region&text=To verify the possibility of,geostationary orbit to disposal orbits.

https://phys.org/news/2018-09-plasma-thruster-space-debris-technology.html#google_vignette

https://www.sciencedirect.com/science/article/abs/pii/S0094576523000553#:~:text=One of the promising ways,to as the ion force.

A Real Life Tractor Beam for Cleaning Up Space Junk

In 1999, astronaut John Crichton (Ben Browder) strapped into the experimental spacecraft Farscape-1 and blasted into orbit. His intended mission, to carry out a high-velocity slingshot maneuver around the planet, was cut short when Crichton fell into a wormhole and emerged in the Uncharted...

www.syfy.com

https://en.wikipedia.org/wiki/Electrolaser (And reference links therein)

https://www.nature.com/articles/s41566-022-01139-z

https://www.nature.com/articles/srep40063

Picatinny engineers set phasers to 'fry'

Scientists and engineers at Picatinny Arsenal, N.J., are busy developing a device that will shoot lightning bolts down laser beams to destroy its target. Soldiers and science fiction fans, you're welcome.

www.army.mil

https://apps.dtic.mil/sti/pdfs/ADA446847.pdf

https://enviroinfo.llnl.gov/sites/e...01/B865AHistoricAmericanEngineeringReport.pdf Excerpt: "The Advanced Test Accelerator (ATA) facility (Building 865A) was built in 1983 to investigate the feasibility of propagating intense electron beams through the atmosphere. Experiments were conducted in the ATA to test electron beams in the open air to determine how beams propagate in natural environments. This was done to consider the potential for military application of electron-beam propagation, in addition to considering the interaction of electron beams with lasers and plasmas. Completed in the fall of 1983, the ATA facility was expanded in 1986 to conduct experiments using Paladin Free Electron Lasers (FELs) for the Strategic Defense Initiative Office (SDIO)." [Note: In 1987, I was briefed on the research at LLNL's ATA during a tour of the facility when I was working on technical assessments of SDI projects. That was when I first heard of the technique of propagating electron beams along laser induced plasma channels in the atmosphere.]

 

[jsport]

Chinese Military Says It’s Figured Out How to Build Laser Weapons That Can Fire Indefinitely

The Chinese military claims it has developed technology that would allow for "infinite" lasers that don't go haywire.

futurism.com

 

[bcredman]

Chinese Military Says It’s Figured Out How to Build Laser Weapons That Can Fire Indefinitely

The Chinese military claims it has developed technology that would allow for "infinite" lasers that don't go haywire.

futurism.com

I'm skeptical of the claim since the article says "The new Chinese cooling system, according to the report, would use gas that blows through the weapon to remove excess heat" because the specific heat capacities of gases are much lower than those of liquids, which is why liquid cooling is used in most high energy lasers.

A hybrid gas-liquid spray cooling system might be workable such as air-atomized spray cooling, which involves nothing more than blowing air with tiny droplets against a hot plate to decrease the temperature of the hot plate.

Certainly a flowing air cooled laser that could maintain the temperature during continuous operation indefinitely would be desirable since it would likely have lower size, weight and power draw than a liquid cooled laser. So, if the Chinese have made even a small advance in that direction, that would be significant even if they haven't really solved the problem yet.

None of the articles I've seen so far online provide a link to the research article in Acta Optica Sinica, which I would like to read to see what the researchers have actually reported about their research.

 

[jsport]

In the Tempest In a Teacup article, the authors seem to have never heard of wake turbulence from aircraft which produces wake vortices in air far from any boundaries and these wake vortices last several minutes before decaying. Wake turbulence and the resulting wake vortices have been studied in flight tests and in wind tunnel tests for many decades.

In the experiments discussed in that article, the ball of turbulence was produced in water, not in a plasma. The molecules of water are neutral, whereas the constituents of plasma are charged. Thus, the configurations used to produce the water turbulence ball may not be applicable to forming a plasma turbulence ball.

Although the article "Pair plasmas found in deep space can now be generated in the lab" says near the beginning "An international team of scientists has developed a novel way to experimentally produce plasma 'fireballs' on Earth," if you read further into the article, you find that they have created beams of electron-positron pairs with densities similar to those found in the deep space plasma "fireballs," but they have not yet created such plasma "fireballs."

The article specifically states "Now, for the first time, an international team of scientists, including researchers from the University of Rochester's Laboratory for Laser Energetics (LLE), has experimentally generated high-density relativistic electron-positron pair-plasma beams by producing two to three orders of magnitude more pairs than previously reported...In other words, the beam they generated in the lab had enough particles to start behaving like a true astrophysical plasma." The MARAUDER concept needs a confined volume of plasma, which is then launched at the target with the plasma remaining confined during launch and transit to the target. That's very different from a beam of plasma.

An electron-positron plasma beam might make a formidable directed energy weapon for use in space if it could be made to work in a compact, low enough mass configuration to be put in space, but the electron-positron beam would not propagate through the atmosphere.

For a kind of "plasma beam" weapon operating in the atmosphere, perhaps a better choice may be the electrolaser: https://en.wikipedia.org/wiki/Electrolaser "An electrolaser is a type of electroshock weapon that is also a directed-energy weapon. It uses lasers to form an electrically conductive laser-induced plasma channel (LIPC). A fraction of a second later, a powerful electric current is sent down this plasma channel and delivered to the target, thus functioning overall as a large-scale, high energy, long-distance version of the Taser electroshock gun...Because a laser-induced plasma channel relies on ionization, gas must exist between the electrolaser weapon and its target. If a laser-beam is intense enough, its electromagnetic field is strong enough to rip electrons off of air molecules, or whatever gas happens to be in between, creating plasma." See also https://www.army.mil/article/82262/ and https://www.bbc.com/news/technology-18630622

Scientists Test System for Controlling Where Lightning Strikes Hit Using Lasers

Turns out, all you need is a million dollar laser that can shoot high energy pulses at an absurdly fast rate, and you can maybe divert lightning.

futurism.com

 

[bcredman]

Scientists Test System for Controlling Where Lightning Strikes Hit Using Lasers

Turns out, all you need is a million dollar laser that can shoot high energy pulses at an absurdly fast rate, and you can maybe divert lightning.

futurism.com

This an interesting advancement on research on triggering and guiding lightning using lasers that has been ongoing for a few decades, as indicated in the earlier 2021 paper by the same group of researchers, available at this link https://www.epjap.org/articles/epjap/pdf/2021/01/ap200243.pdf :

A continuously operating technique to trigger lightning would therefore be highly desirable. Lasers were identified very early as candidates for this purpose. The first tests performed in the 1970s using “long” laser pulses of several nanoseconds or more demonstrated the guiding of megavolts discharges with lengths of up to 2 m [9,10]. An attempt to trigger and guide natural lightning was made by Uchida et al. in 1999 using a combination of three lasers with a kJ-level energy to form a 2 m long plasma spark at the tip of an experimental tower [11]. The researchers reported two successful events, but this low number of events did not lead to conclusive proof of the effectiveness of the lightning triggering technique. This approach was progressively abandoned because of the discontinuous profile of the plasma generated with such “long” IR or mid-IR pulses through avalanche ionization and the huge laser energy required to extend the laser-generated plasma column beyond a few meters.

In contrast, sub-100 fs laser pulses are short enough to prevent electron avalanche. The generated plasma remains therefore transparent to the laser pulse. As a consequence, ionizing self-guided filaments can exceed 100 m in length. Filamentation is a self-guided, non-linear propagation mode that relies on the dynamic balance between the optical Kerr effect that tends to focus the laser beam and self-defocusing, mainly due to the plasma generated when the pulse intensity becomes sufficiently high [12–16]. It results in the long range propagation of a pulse with multi-GW peak intensity. A plasma track and a low air density channel are left in the wake of the pulse. These ionized light filaments can be generated at a distance of several kilometers [17], and can cover a length of more than a hundred meters [18] by an adequate choice of the laser parameters. They can be directed to any position in the atmosphere by sweeping the beam using a steering mirror.

In the 2000s, several groups demonstrated their capability to trigger high-voltage discharges over several meters with laser pulses of only 100 mJ [19–21]. By electrically connecting two electrodes that were several meters apart, the laser filaments reduce the breakdown voltage by 30% [21], triggering the discharge in conditions that would not have allowed them to without the laser. These triggered discharges are guided along the laser filaments rather than following the erratic path typical of a classical electric discharge. Furthermore, filaments are able to divert a discharge from its preferential path [22].

Based on these successful results on a laboratory scale, a mobile, femtosecond-terawatt laser, “Teramobile”, was developed [23,24]. In a field campaign at the Langmuir Laboratory of the New Mexico Tech on the South Baldy Peak, micro-discharges synchronized with the laser pulses were detected, showing that laser filaments initiated corona discharges in thunderclouds [25]. However, the short lifetime of plasma filaments (typically a few ns) prevented the initiation of upward leaders similar to the mechanism of rocket triggering. Increasing the plasma lifetime by heating the filament plasma with an additional, high-energy nanosecond laser was proposed by several groups [19,26–29]. However, this requires an additional laser of high energy, typically in the joule range. Coupling such a beam into the filament proved to be unpractical over distances exceeding a few meters.

On the other hand, filamentation initiates a low-density(air-depleted) channel [30–33]. For a low-repetition rate multi-TW laser, the air density is initially reduced by a factor of 5 over a typical length of a few meters. The density depletion still amounts to typically 10% of the ambient pressure after 1 ms. These straight, low-density channels favor the triggering and guiding of electric discharges in the atmosphere at a 60% reduced voltage [22,34]. At repetition rates in the kHz range, the depletion of the air density due to filamentation is amplified by a cumulative effect [32]. As a result, increasing the repetition rate of 100 mJ, 1030 nm laser pulses from 10 Hz to 1 kHz reduces the laser-induced breakdown voltage by a factor of 3 [35]. Therefore, a terawatt laser at a kilohertz repetition rate would allow the formation of a permanent low-density channel likely capable of guiding discharges over long distances. Based on these results, we decided to investigate the impact of laser filamentation at a kHz repetition rate on lightning strikes, in real scale. More specifically, within the Laser Lightning Rod (LLR) project [36] we focus on developing a kHz-terawatt laser system and assessing its ability to stimulate upward lightning flashes from the grounded,123 m tall telecom tower at Santis, Switzerland, in order to initiate and guide the lightning strikes.

 

[bcredman]

This an interesting advancement on research on triggering and guiding lightning using lasers that has been ongoing for a few decades, as indicated in the earlier 2021 paper by the same group of researchers, available at this link https://www.epjap.org/articles/epjap/pdf/2021/01/ap200243.pdf

Here is a link to their 2023 paper in Nature to which the Futurism article was referring: https://www.nature.com/articles/s41566-022-01139-z

 

[publiusr]

It turns out that sound waves can direct electricity as well:

View: https://www.youtube.com/watch?v=O2-vrixoiHE

https://phys.org/news/2025-02-invisible-electric-wire-electricity.html

Previously, sparks could only be guided with laser induced discharges colloquially called "electrolasers," which required the use of dangerous lasers, as well as precise timing between the laser and the electric discharge. The developed method uses ultrasound rather than lasers, and it is safe for the eyes and skin. The equipment is compact, affordable and can be operated continuously.

For firefighting?

https://techxplore.com/news/2025-02-device-electrically.html

 

[bcredman]

It turns out that sound waves can direct electricity as well:

View: https://www.youtube.com/watch?v=O2-vrixoiHE

https://phys.org/news/2025-02-invisible-electric-wire-electricity.html

Previously, sparks could only be guided with laser induced discharges colloquially called "electrolasers," which required the use of dangerous lasers, as well as precise timing between the laser and the electric discharge. The developed method uses ultrasound rather than lasers, and it is safe for the eyes and skin. The equipment is compact, affordable and can be operated continuously.

For firefighting?

https://techxplore.com/news/2025-02-device-electrically.html

That's cool. The paper on this at https://www.science.org/doi/10.1126/sciadv.adp0686 explains:

The air in the vicinity of the plasma streamer is heated up, which is the result of collisions between the charged particles accelerated by an electric field and other neutral air molecules (22). The heated air has a different acoustic impedance than the surrounding air since they have different temperatures and, thus, densities and traveling speed of sound. This leads to the appearance of an acoustic radiation force that pushes the hot air into the antinodes. This phenomenon has been reported between different gasses, where the gas with less acoustic impedance gets trapped in the antinodes of a standing wave (23)...

In summary, the electric spark heats up the air; this heated air expands, thus decreasing in density; the heated lower-density air is shaped by the ultrasonic field that pushes it to the high-amplitude regions; and the region of lower-density air is a preferred discharge path. This is in line with laser-guided discharge (20), but the heated lower-density region of air is created by the spark itself and shaped by the ultrasonic field...

The electric spark used in the experiments is an alternating current of 2.3 MHz with a square amplitude modulation ranging from 50 to 4000 Hz (figs. S10 and S11). The ultrasonic field had an effect on a dc spark, but it was not capable of guiding it. We tested a spark with a gap of 2 cm at 60 kV (see fig. S12); other dc sparks with smaller gaps using 4 kV (EMCO cube) or 11 kV (High Voltage, Dekaim) could not be guided either. We think that this is due to the ionic wind (25) created between the pair of electrodes. We consider this a limitation, yet the applications described throughout this paper operate with ac sparks...

With ultrasound, we have guided ac rather than dc as is the case in laser-guided discharges. ac has the advantage of not requiring a pair of electrodes between the discharge or having to ground the target; we note however that it can limit some applications related to high-power electronics that only operate with dc.
________________________________________________________________________

The fire fighting vortex launcher is also cool, but it works on a different principle: this device works to suppress flames using the power of conductive aerosols, small particles that can direct electricity. These aerosols are carried by vortex rings—small donut-shaped bands of air—that transform the particles into short pulses of wind that convert nearby oxygen into ozone. Once released, their accelerated airflow generates rapid turbulence, disrupting the natural combustion process and quickly extinguishing the target fire, said John LaRocco, lead author of the study and a research scientist in psychiatry at The Ohio State University College of Medicine.

The paper they published https://www.mdpi.com/2227-7080/13/1/10 states: Ionizing the air in short, pulsed electric arcs generates rapid, turbulent airflow. The turbulent airflow generated by electric arcs ionizing the air can act rapidly to extinguish flames [20]. Expanding the distance of an electric arc can potentially improve the range of the effect...

a high-voltage alternating current has been explored as a potential fire extinguishing system. In particular, applied electricity generates an ionic wind sufficient to effectively extinguish diffusion flames in enclosed locations [9,20,21]. The impedance of the air requires a high voltage to generate a sufficient spark gap. Even with a high-voltage source, the electrodes must be positioned precariously close to the flames [21], which increases the danger to the firefighter, as well as negating the potential advantages of the new tool [9]. Extending the range of the electric arc can provide the advantages of current firefighting methods, as well as any benefits of a newer method...

As a vortex ring can carry conductive substances, it could potentially extend the range of an electric arc and, with it, the fire-extinguishing properties of the ionic wind. Thus, the combination of both a vortex ring and an ionic wind could potentially enhance the firefighting advantages of both techniques. A vortex ring generator with aerosolized conductive materials can extend the range of an electrical arc while acting as a fire extinguishing modality.
_______________________________________________________________________

Could the conductive aerosol vortex ring be combined with the sound wave guiding used to guide the spark produced plasmas? Perhaps, if the electricity produced by the conductive aerosols in order to convert oxygen into ozone also heats the air containing the aerosols reducing the density of the air containing the aerosols, then the sound wave should push those lower density regions toward the high-amplitude regions of the acoustic field. The paper on the conductive aerosol vortex ring mentioned "a high-voltage alternating current" and stated that the experimental setup they used "operated at 300 Hz with a 40% duty cycle" so it sounds like they are using AC electricity as required for the sound guiding effect to work.

It sounds like an interesting and possibly fruitful research topic.

Note, however, the sentences in the paper on the firefighting device: "In particular, applied electricity generates an ionic wind sufficient to effectively extinguish diffusion flames in enclosed locations...As a vortex ring can carry conductive substances, it could potentially extend the range of an electric arc and, with it, the fire-extinguishing properties of the ionic wind. Thus, the combination of both a vortex ring and an ionic wind could potentially enhance the firefighting advantages of both techniques." and the sentence in the paper on the sound guiding of sparks: "The ultrasonic field had an effect on a dc spark, but it was not capable of guiding it...We think that this is due to the ionic wind (25) created between the pair of electrodes." If the firefighting device depends on generating an ionic wind and the ionic wind precludes sonic guiding, then the two techniques may be very difficult to combine.

 

[publiusr]

I’d like to see an electrolaser with sonic technology—anything to get rid of wires—like here:

Lorentz Cannon Fires Lightning

[Editor’s note: This video disappeared, but it has been archived here. We’re leaving the original links as-were in case they come back up.] The aptly named [LightingOnDemand] has create…

hackaday.com

 

[bcredman]

I’d like to see an electrolaser with sonic technology—anything to get rid of wires—like here:

Lorentz Cannon Fires Lightning

[Editor’s note: This video disappeared, but it has been archived here. We’re leaving the original links as-were in case they come back up.] The aptly named [LightingOnDemand] has create…

hackaday.com

You may have your wires crossed. (Pun intended ) The electrolaser and the sonic guiding of plasmas are separate technologies for guiding plasmas, neither requires the other, so "an electrolaser with sonic technology" is a misnomer. Each of those technologies does not use wires, unlike the Lorentz cannon. Thus, the wires have already been gotten rid of by each of those technologies. However, I don't know how each of the three technologies compares in terms of capabilities for power delivery on target, lethality, and standoff range.

https://en.wikipedia.org/wiki/Electrolaser "An electrolaser is a type of electroshock weapon that is also a directed-energy weapon. It uses lasers to form an electrically conductive laser-induced plasma channel (LIPC). A fraction of a second later, a powerful electric current is sent down this plasma channel and delivered to the target, thus functioning overall as a large-scale, high energy, long-distance version of the Taser electroshock gun .

For sonic guiding of plasmas, "The developed method uses ultrasound rather than lasers."

 

[publiusr]

I was thinking of jacketing…surrounding a beam with sonics or vice versa…they might help each other (or interfere.)

Adam Savage even used a stream of water

 

[bcredman]

I was thinking of jacketing…surrounding a beam with sonics or vice versa…they might help each other (or interfere.)

Adam Savage even used a stream of water

I see. That's an interesting idea.

It may be difficult for them to help each other since sonics and lasers generally have much different ranges of operation with laser beams having longer ranges than sonic beams in air and the reverse in water. Still, perhaps there has been some research on this of which I am unaware.

The "or interfere" is intriguing to me in that perhaps a sonic emitter on the target could locally disrupt an electrolaser's laser induced plasma channel in the region of the target preventing it from making the electrical connection to the target needed to deliver the shock to the target. That might be a possible countermeasure to the electrolaser weapon.

 

[bcredman]

I see. That's an interesting idea.

It may be difficult for them to help each other since sonics and lasers generally have much different ranges of operation with laser beams having longer ranges than sonic beams in air and the reverse in water. Still, perhaps there has been some research on this of which I am unaware.

The "or interfere" is intriguing to me in that perhaps a sonic emitter on the target could locally disrupt an electrolaser's laser induced plasma channel in the region of the target preventing it from making the electrical connection to the target needed to deliver the shock to the target. That might be a possible countermeasure to the electrolaser weapon.

One thing that might prevent the sonic beam from either helping or interfering with the laser induced plasma channel is that when the laser forms the plasma channel it creates a sonic boom shock wave which might disrupt the sonic beam.

Also, below is Google Chrome's AI response to my inquiry "guiding of laser induced plasma channel with sound," but note that none of the references that were in the side panel of the AI's response discussed guiding the plasma channel using sound waves, so this response could be an AI hallucination:

Guiding a laser-induced plasma channel with sound is a concept where sound waves, through their pressure fluctuations, can manipulate the path of a laser-created plasma channel by subtly altering the air density along the laser beam's trajectory, essentially "steering" the plasma filament in a desired direction; this is a relatively new and actively researched area with potential applications in fields like lightning protection and directed energy weapons.

How it works:

• Plasma creation:
  When a high-intensity laser beam interacts with air, it ionizes the molecules, creating a plasma channel along the laser path - a highly conductive pathway for electricity.
  
  
• Sound wave influence:
  By directing a sound wave alongside the laser beam, the pressure variations from the sound can locally compress or rarefy the air, creating slight density gradients along the laser path.
  
  
• Plasma channel manipulation:
  These density variations influence how the laser beam interacts with the air, subtly bending the plasma channel towards areas of higher density, effectively steering its path.
  

Key points about guiding laser plasma with sound:

• Precision is crucial:
  Precise control over the sound wave's frequency and amplitude is necessary to achieve accurate plasma channel manipulation.
  
  
• Limited range:
  Due to sound wave attenuation over distance, this technique is likely most effective for guiding plasma channels over relatively short distances.
  
  
• Potential applications:
  • Lightning protection: Guiding lightning strikes away from vulnerable structures using a laser-induced plasma channel steered by sound waves.
    
    
  • Directed energy weapons: Precisely directing high-energy laser beams by manipulating the plasma channel path.
    
    
  • Plasma-based particle accelerators: Controlling the plasma channel for optimized particle acceleration.
    

Challenges:

• Complex physics:
  The interaction between laser beams, plasma, and sound waves is intricate and requires sophisticated modeling to fully understand.
  
  
• Experimental limitations:
  Generating high-power sound waves with precise spatial control can be challenging.

 

[bcredman]

Note the following statement in the article at https://www.army.mil/article/82262/...eam is,challenges were many, Fischer recalled.

"If a laser beam is intense enough, its electro-magnetic field is strong enough to rip electrons off of air molecules, creating plasma," said Fischer. "This plasma is located along the path of the laser beam, so we can direct it wherever we want by moving a mirror."

Moving a mirror sounds a lot easier than generating the strong sound field to guide the laser induced plasma channel.

 

[siegecrossbow]

PLAN is testing a high power laser prototype on a Type-071. Previously it has been thought that they’d use HQ-10 for point defense but they dragged that out so long for budgetary reason that something fancier was ready technologically.

View attachment 737465
With protective dome on.

View attachment 737466

Without dome.

Spotted out to sea. Weapons trial or possibly in service?

 

[Cordy]

Still Unhappy With Progress On Directed Energy Weapons, SWO Boss Wants More Land Based Testing To Speed Use On Ships - Defense Daily

Laser and high-powered microwave systems are key to increasing magazine depth aboard ships to defend themselves and other assets, but the technologies are

www.defensedaily.com

It would appear the Defense News Feb 4 article below gives a totally misleading impression in claiming "US Navy hits drone with the "high energy" laser in successful test" in 2024
with the USN Lockheed HELIOS 60-150kw laser if we are to believe Adm. Daryl Caudle, commander of US Fleet Forces Command who told reporters post test at the Jan. '25 Surface Navy Association’s annual symposium in saying the state of the Navy's shipboard laser effort is embarrassing as lasers have been under development since the '80's and as yet unable to find an acceptable way to actually take out missile systems.

https://www.defensenews.com/news/yo...s-drone-with-helios-laser-in-successful-test/

 

[bring_it_on]

The DOTE report from 2024 :

CCM supported the Navy’s demonstration on USS Preble (DDG 88) to verify and validate the functionality, performance, and capability of the HEL with Integrated Optical Dazzler and Surveillance system against an unmanned aerial vehicle target.CCM collected imagery of the engagements to support the evaluation of system performance.

Adding a prototype HEL on an operational vessel comes with its own challenges in terms of setting up tests and meeting schedules. With lower power systems (100kW and below) its probably still doable..but those 300+ kW systems that will come later this decade or later will need a lot more testing given both an expanded threat set and types of effects. If you want reasonable schedules and testing cadence you should probably have a dedicated test vessel supporting this.

Adm. Daryl Caudle, commander of US Fleet Forces Command who told reporters post test ...

Navy admirals need to understand their own service's limitations when it comes to incorporating effective high energy lasers onboard ships. Their inability to field affordable next generation combatants limits their ability t get something that's optimized for defeating anti ship missiles (like Army's 300kW IFPC HEL or the OSD sponored 500kW efforts). They cancelled DDG-1000 class, and continue to buy 'maxed' out DDG-51's so they will have to stick to sub 100kW HELs on these vessels. The Frigate has margin for a HEL..but its more HELIOS class probably and even that they have not funded on the first ships so is probably a mid to late 2030s capability given how long it takes them to build ships. While operating HEL's in a maritime environment is hard, it is not the maturity of HEL's that is going to be the limiting step in the Navy's adoption of the tech. Its the services and its industrial base's inability to incorporate those owing to factors outlined above.

 

[bcredman]

It would appear the Defense News Feb 4 article below gives a totally misleading impression in claiming "US Navy hits drone with the "high energy" laser in successful test" in 2024
with the USN Lockheed HELIOS 60-150kw laser if we are to believe Adm. Daryl Caudle, commander of US Fleet Forces Command who told reporters post test at the Jan. '25 Surface Navy Association’s annual symposium in saying the state of the Navy's shipboard laser effort is embarrassing as lasers have been under development since the '80's and as yet unable to find an acceptable way to actually take out missile systems.

https://www.defensenews.com/news/yo...s-drone-with-helios-laser-in-successful-test/

A drone is not a missile.

A drone is a very slow and soft target compared to a missile. A laser system that demonstrates successfully taking out a drone, does not imply that the said laser system can take out a missile.

There is no contradiction between the Defense News Feb 4 article and Adm. Daryl Caudle's statement.

 

[bcredman]

The DOTE report from 2024 :



Adding a prototype HEL on an operational vessel comes with its own challenges in terms of setting up tests and meeting schedules. With lower power systems (100kW and below) its probably still doable..but those 300+ kW systems that will come later this decade or later will need a lot more testing given both an expanded threat set and types of effects. If you want reasonable schedules and testing cadence you should probably have a dedicated test vessel supporting this.



Navy admirals need to understand their own service's limitations when it comes to incorporating effective high energy lasers onboard ships. Their inability to field affordable next generation combatants limits their ability t get something that's optimized for defeating anti ship missiles (like Army's 300kW IFPC HEL or the OSD sponored 500kW efforts). They cancelled DDG-1000 class, and continue to buy 'maxed' out DDG-51's so they will have to stick to sub 100kW HELs on these vessels. The Frigate has margin for a HEL..but its more HELIOS class probably and even that they have not funded on the first ships so is probably a mid to late 2030s capability given how long it takes them to build ships. While operating HEL's in a maritime environment is hard, it is not the maturity of HEL's that is going to be the limiting step in the Navy's adoption of the tech. Its the services and its industrial base's inability to incorporate those owing to factors outlined above.

Thanks bring_it_on.

This explains that the laser weapons that are needed to defeat anti-ship missiles require much higher powers (~300kW - 500kW) than the laser weapons that are only capable of defeating drones (~50kW to ~150kW) like the HELIOS laser weapon on the Preble.

This supports my response to Cordy that "A laser system that demonstrates successfully taking out a drone, does not imply that the said laser system can take out a missile. There is no contradiction between the Defense News Feb 4 article and Adm. Daryl Caudle's statement."

In addition, the article states that it is not the state of the maturity of the high energy laser systems that is going to be the limiting step in the Navy's adoption of the tech, "Its the services and its industrial base's inability to incorporate those owing to factors outlined above."

 

[siegecrossbow]

A drone is not a missile.

A drone is a very slow and soft target compared to a missile. A laser system that demonstrates successfully taking out a drone, does not imply that the said laser system can take out a missile.

There is no contradiction between the Defense News Feb 4 article and Adm. Daryl Caudle's statement.

You can still take out optical sensors on missiles for mission kill.

 

[bcredman]

You can still take out optical sensors on missiles for mission kill.

Yes, but even drone hardbody killer laser power levels are overkill for taking out optical sensors.

Such systems designed for defeating optical sensors are called active Electro-Optical CounterMeasure (EOCM), InfraRed CounterMeasure (IRCM), Directed IRCM (DIRCM) and dazzler systems, some of which use laser sources and some of which use other, incoherent sources. Active EOCM, IRCM, DIRCM and laser dazzler systems require lower power beams than do laser systems designed for hardbody kill even for drones.

Active EOCM, IRCM and DIRCM systems have been deployed on military platforms for decades.

Currently, the Navy has eight Optical Dazzling Interdictor, Navy (ODIN) laser dazzlers, which disrupt enemy sensors, integrated into Arleigh Burke-class destroyers, according to the Congressional Research Service’s December 2024 report on Navy lasers. ODIN was first deployed on active service vessels in 2020. ODIN uses a 30kW laser.

Note that for a stationary or slow-moving target (like a ship), depending on where on the missile's trajectory it occurs, disruption of the missile's sensors may not prevent the missile from hitting its target, especially if the missile's inertial guidance system has locked onto the target's last position update before the sensor was disrupted, or if the missile can switch to other guidance modes like radar or GPS guidance.

In addition, unlike with electronic and radar countermeasures, directed beam optical and IR countermeasures can only be effectively deployed where the optical sensor is looking, which is usually at the missile's target. Hardbody kill directed energy weapons can be deployed by any asset that has line of sight to the missile within the weapon's range, so missiles may be destroyed by assets that are not directly targeted by the missile.

 

[bring_it_on]

Lockheed Martin has al

This explains that the laser weapons that are needed to defeat anti-ship missiles require much higher powers (~300kW - 500kW) than the laser weapons that are only capable of defeating drones (~50kW to ~150kW) like the HELIOS laser weapon on the Preble.

There have been demonstrated kills of missile class UAS's with 50-60kW sized HEL's. Lockheed Martin did that recently. This is unlike a kinetic intercept, you first have to define what effect are you looking for under what scenarios (against vulnerable aspects of weapons, head on, side shot etc etc). To go after some of the higher performing cruise missiles with reasonable dwell times and desired effects (mission kills and target destruction) you have to go to the 100kW class and above. US Army scaled its 100kW class IFPC HEL requirements to cover 300kW to defeat the broader threat.

 

[bcredman]

Lockheed Martin has al


There have been demonstrated kills of missile class UAS's with 50-60kW sized HEL's. Lockheed Martin did that recently. This is unlike a kinetic intercept, you first have to define what effect are you looking for under what scenarios (against vulnerable aspects of weapons, head on, side shot etc etc). To go after some of the higher performing cruise missiles with reasonable dwell times and desired effects (mission kills and target destruction) you have to go to the 100kW class and above. US Army scaled its 100kW class IFPC HEL requirements to cover 300kW to defeat the broader threat.

Please provide a link or reference that reports the missile kill by the 50-60kW HEL from Lockheed Martin.

Was it a hardbody kill, which is what I have been talking about requiring 300 kW or more, or disruption of the missile's optical sensors, which can be done even at 30 kW power levels?

 

[bring_it_on]

Inside the Lockheed Martin Laser Technology

Lockheed Martin’s LLD system, has done what no other ground-based electric laser weapon system has done before: defeated two surrogate cruise missiles.

www.lockheedmartin.com

 

[bcredman]

Inside the Lockheed Martin Laser Technology

Lockheed Martin’s LLD system, has done what no other ground-based electric laser weapon system has done before: defeated two surrogate cruise missiles.

www.lockheedmartin.com

View attachment 759403

Thanks.

The articles states "During the demonstration, the LLD tracked and defeated high-speed drones representative of subsonic cruise missiles."

The question is how representative of subsonic cruise missiles were these drones? The answer is not very; they were representative of the speed and maneuverability of the cruise missiles, but not their hardbody materials and construction. The test demonstrates the capability of tracking and keeping the laser beam pointed on a surrogate target with subsonic cruise missile flight characteristics, but does not demonstrate that this laser could defeat an actual subsonic cruise missile. See details below. This is just another drone kill demo.

The video in the article states that the target is an MQM-107. According to Wikipedia: 'The MQM-107 is designed as a high-subsonic target drone, featuring a slight sweep in the wings and a centerline mounted turbojet engine. The drone is launched from the ground with a rocket booster accelerating it until the jet engine takes over. It can be recovered by parachute and reused...Production of the MQM-107 ended in 2003, and the current inventory is being phased out in favor of its replacement, the BQM-167 Skeeter.'

According to https://www.globalsecurity.org/military/systems/munitions/mqm-107.htm : 'The fuselage construction is aluminum with bonded honeycomb wing and tail surface, and plastic nose and tail cones. The airframe was designed with constant attention to minimizing initial fabrication and refurbishment costs. The simplicity and modularity of its construction demonstrates the success of this attention. The airframe may be divided into seven major parts -- the nose section, fuel tankage, aft section, wing, empennage, engine nacelle, and aerodynamic fairings. The forward section of the fuselage houses the crushable nose cone, electronics compartment, payload section, and smoke oil tank. The center section is the fuel tank and the rear area is the recovery system...

Known as the Army’s workhorse, the most versatile subscale aerial target in the TMO repertoire is the MQM-107 Streaker. It is capable of performing advanced maneuvers up to transonic speeds.'

 

[bring_it_on]

The demonstrations served their purpose. Scoring brownie points on forums wasn’t it. Validating internal models, and demonstrating performance to service customers was.The Navy will test HELIOS against a range of threats to gauge its effectiveness in various scenarios. Also worth noting that HELIOS is 60kW scalable to 120kW. Beyond that, Lockheed has already OSD / DOD funded efforts in the 300kW and 500kW classes and has a business arrangement to market the 100kW class Iron Beam in the US for land based applications.

 

[indicisivedivide]

Thanks.

The articles states "During the demonstration, the LLD tracked and defeated high-speed drones representative of subsonic cruise missiles."

The question is how representative of subsonic cruise missiles were these drones? The answer is not very; they were representative of the speed and maneuverability of the cruise missiles, but not their hardbody materials and construction. The test demonstrates the capability of tracking and keeping the laser beam pointed on a surrogate target with subsonic cruise missile flight characteristics, but does not demonstrate that this laser could defeat an actual subsonic cruise missile. See details below. This is just another drone kill demo.

The video in the article states that the target is an MQM-107. According to Wikipedia: 'The MQM-107 is designed as a high-subsonic target drone, featuring a slight sweep in the wings and a centerline mounted turbojet engine. The drone is launched from the ground with a rocket booster accelerating it until the jet engine takes over. It can be recovered by parachute and reused...Production of the MQM-107 ended in 2003, and the current inventory is being phased out in favor of its replacement, the BQM-167 Skeeter.'

According to https://www.globalsecurity.org/military/systems/munitions/mqm-107.htm : 'The fuselage construction is aluminum with bonded honeycomb wing and tail surface, and plastic nose and tail cones. The airframe was designed with constant attention to minimizing initial fabrication and refurbishment costs. The simplicity and modularity of its construction demonstrates the success of this attention. The airframe may be divided into seven major parts -- the nose section, fuel tankage, aft section, wing, empennage, engine nacelle, and aerodynamic fairings. The forward section of the fuselage houses the crushable nose cone, electronics compartment, payload section, and smoke oil tank. The center section is the fuel tank and the rear area is the recovery system...

Known as the Army’s workhorse, the most versatile subscale aerial target in the TMO repertoire is the MQM-107 Streaker. It is capable of performing advanced maneuvers up to transonic speeds.'

Well it did keep track of the drone which can mimic the flight characteristics of a subsonic missile. Now the power must be raised but the problem is if the enemy changes the material of the missile body which might complicate efforts.

 

[bring_it_on]

Well it did keep track of the drone which can mimic the flight characteristics of a subsonic missile. Now the power must be raised but the problem is if the enemy changes the material of the missile body which might complicate efforts.

Its not hard to test performance against various materials to develop your models. The DOD has efforts that do just that. That said, there's no such thing as free lunch and changes to materials and HEL-hardening efforts will come at a cost to the cruise missile, UAV etc. It also remains to be seen whether those can be applied to tens of thousands of missiles already operational.

 

[Cordy]

Inside the Lockheed Martin Laser Technology

Lockheed Martin’s LLD system, has done what no other ground-based electric laser weapon system has done before: defeated two surrogate cruise missiles.

www.lockheedmartin.com

View attachment 759403

Interesting read on the advanced Lockhead LLD beam control system including its target illuminator laser (TILL) which uses a fine tracking telescope for engagement quality tracking of targets. Would appear to me as having to use an optical telescope a major limitation. The Army is developing the airbase defense (a bone of contention between the Air Force and Army, whose current responsibility it is) with a hypervelocity projectile cannon, the MDAC AA program originally conceived by the Pentagon Strategic Capabilities Office to improve integrated air and missile defense and claiming reduced overall costs and increasing flexibility, to defend against enemy aircraft, missiles, artillery projectiles, and UAVs, the reason given with its multi-function high definition radar it will be operational at long ranges and in bad weather conditions like heavy rain, cloud, snow, wind, and dust, not possible with LLD?

Note the Army plan to use the BAE saboted Hypervelocity Projectile in the planned and the under test wheeled 155-millimeter artillery systems and the HVP can be fired from the 5-inch deck guns on Burkes.

 

[Forest Green]

As Israel fields Iron Beam, Gulf states are pining for the technology

“There has been a shared interest in so far as most would want to have them, they are high on the priority list of most regional states," one expert said.

www.defensenews.com

 

[Forest Green]

For what application/mission?

If your question is in response to the article Still Unhappy With Progress On Directed Energy Weapons..., the answer is No, particle beams would not be more effective than lasers or microwaves for the shipborne or land based air defense since particle beams cannot propagate very far in the atmosphere because of scattering.

A what particle mass does scattering cease being an issue? Because a device used by First Light Fusion to fire fusion pellets made be wonder if something like that could be used, with a muzzle velocity of about 60km/s.

 

[bcredman]

Interesting read on the advanced Lockhead LLD beam control system including its target illuminator laser (TILL) which uses a fine tracking telescope for engagement quality tracking of targets. Would appear to me as having to use an optical telescope a major limitation. The Army is developing the airbase defense (a bone of contention between the Air Force and Army, whose current responsibility it is) with a hypervelocity projectile cannon, the MDAC AA program originally conceived by the Pentagon Strategic Capabilities Office to improve integrated air and missile defense and claiming reduced overall costs and increasing flexibility, to defend against enemy aircraft, missiles, artillery projectiles, and UAVs, the reason given with its multi-function high definition radar it will be operational at long ranges and in bad weather conditions like heavy rain, cloud, snow, wind, and dust, not possible with LLD?

Note the Army plan to use the BAE saboted Hypervelocity Projectile in the planned and the under test wheeled 155-millimeter artillery systems and the HVP can be fired from the 5-inch deck guns on Burkes.

The typical target tracking architecture since the 1980s has been microwave radar for long range tracking with handover to passive infrared and/or millimeter wave (mm-wave) radar tracking sensors at moderate ranges for finer resolution tracking and target classification.

Until the early 2000s, lasers were used mostly for relatively short range (compared to radar and passive IR ranges) range finding, target designation and guiding of laser guided bombs. Although, these laser sensors could not operate through heavy fog, clouds, and dust*, during conditions in which they could be used, their use improved hit and kill probabilities so much, that the services spent the money needed to field them on various military platforms.

Since the late 2000s, lidar technology started becoming mature enough for deployment for short range navigation, autonomous vehicle guidance and collision avoidance and target identification missions.

With the development of relatively compact weapons grade solid state lasers starting in about the early 2010s, it became apparent that radar, IR and mm-wave radar lacked the tracking accuracy to keep the laser beam on the desired laser spot location on the target. Since the laser weapon itself uses a large aperture optical system with adaptive optics for accurate and stable pointing through turbulent atmospheres, using low-power laser tracking to accurately guide the high energy laser pointing system was a natural fit since both have degraded performance in fog, clouds and dust. The laser tracking system still requires handover from the moderate range passive IR or EO tracking systems, which in turn get handover from long range radar tracking system.

I am not familiar with the multi-function high definition radar, so I cannot comment on how accurately it can track targets compared to conventional microwave radars, mm-wave radars, passive IR and EO sensors, or laser trackers.

*Note that rain, snow and sleet are not as problematic for lasers as they are for mm-wave radar because the particle sizes are on the same order as the wavelength of mm-wave radar which makes those particles efficient scatters of mm wavelength electromagnetic waves. In addition, there is a relatively large amount of air space between rain drops, snow flakes, and sleet so that the overall attenuation for a laser beam is moderate, and methods for dealing with the laser backscatter from those particles have been developed and used for a long time.

 

[publiusr]

Now with the double slit experiment, we see zones of interference.

I wonder if that can be true for sonics

https://phys.org/news/2025-02-entangling-physically-resonators-enables-major.html

When light shows interference--have the sonics at their strongest--vice versa---better containment?

Lasers in the news

https://phys.org/news/2025-02-technique-laser-thz-air.html

https://phys.org/news/2025-02-discovery-laser-plasma.html

Negative refraction

https://phys.org/news/2025-02-atomic-arrays-enable-negative-refraction.html

Optics today

https://phys.org/news/2025-02-invisible-electro-optic-cavities.html

https://phys.org/news/2025-02-molecules-circular-3d-displays.html

https://techxplore.com/news/2025-02-recyclable-artificial-vision-honey-electrolyte.html

https://techxplore.com/news/2025-02-electromagnetic-absorber-terahertz-technology-future.html

https://phys.org/news/2025-02-quantum-successfully-particle.html

https://phys.org/news/2025-02-mathematical-solutions-2d-interaction-photonic.html

https://phys.org/news/2025-02-fabrication-method-advances-high-photon.html

https://medicalxpress.com/news/2025-02-high-tech-video-optimization-brain.html

 

[bcredman]

A what particle mass does scattering cease being an issue? Because a device used by First Light Fusion to fire fusion pellets made be wonder if something like that could be used, with a muzzle velocity of about 60km/s.

I don't know the answer to your question, but here are some considerations:

1. First Light Fusion's projectiles are used in a high vacuum.

2. Typical atmospheric aerosols range in size from a few tens of nanometers—less than the width of the smallest viruses—to several tens of micrometers—about the diameter of human hair. At the large end of that size range, there are mineral dust, smoke and ash. I would think projectiles would need to at least an order of magnitude larger than atmospheric aerosols to have low scattering in the atmosphere, so that would say they would need to be at least several hundred micrometers wide. Using sand dust as a typical heavy, large particle aerosol, the density of sand is about 2 g/cm^3, and with a radius of 100um, the mass of the sand particle would be m_s = (2g/cm^3)*(4/3)*pi*(0.01cm)^3 = 8.4 ug. Rounding this to 10 ug, and saying the projectile should be at least an order of magnitude heavier than this yields a minimum projectile mass on the order of 100 ug = 0.1 mg. The density of copper is about 9 g/cm^3, so a copper projectile with a volume of at least 0.1mg/(9000 mg/cm^3) = 1.1E-5 cm^3 would be needed. For a spherical copper projectile, the radius would need to be at least [(3/4)*(1/pi)*(1.1e-5 cm^3)]^(1/3) = 0.0138 cm = 138 um, and rounding that to 140 um radius gives a diameter of about 280 um.

3. At 60 km/s in the atmosphere, depending on the projectile material, there will be some minimum projectile size required such that the aero-heating does not vaporize the whole projectile. So, to analyze this, let's look at meteroids: https://science.howstuffworks.com/question486.htm
'Meteoroids enter the atmosphere at extremely high speeds -- 7 to 45 miles per second (11 to 72 kilometers per second). They can travel at this rate very easily in the vacuum of space because there's nothing to stop them. Earth's atmosphere, on the other hand, is full of matter, which creates a great deal of friction on a traveling object. This friction generates enough heat (up to 3,000 degrees Fahrenheit, or 1,649 degrees Celsius) to raise the meteoroid's surface to its boiling point, so the meteoroid is vaporized, layer by layer...

So how big does a meteoroid have to be to make it to the surface of the Earth? Surprisingly, most of the meteoroids that reach the ground are especially small -- from microscopic debris to dust-particle-size pieces. They don't get vaporized because they are light enough that they slow down very easily. Moving about 1 inch (2.5 centimeters) per second through the atmosphere, they don't experience the intense friction that larger meteoroids do. In this sense, most all meteoroids that enter the atmosphere make it to the ground, in the form of microscopic dust.

As for meteoroids big enough to form visible meteors, estimates for the minimum size vary. This is because there are factors other than size involved. Most notably, a meteoroid's entry speed affects its chances of reaching the surface, because it determines the amount of friction the meteoroid experiences. Typically, though, a meteoroid would have to be about the size of a marble for a portion of it to reach the Earth's surface. Smaller particles burn up in the atmosphere about 50 to 75 miles (80 to 120 kilometers) above the Earth.'

This tells us that dust-particle-size (several tens of micrometers) projectiles moving at 60 km/s would probably slow down too much in the atmosphere to be useful as a weapon in the atmosphere. Projectiles of sizes between about a few hundred micrometers and 15 mm (just under the standard marble diameter of 16 mm), would mostly vaporize, making them useless as a weapon in the atmosphere. A 16 mm diameter copper sphere would weigh about 39 g. At this size, we are no longer talking about a particle beam type weapon, but more of a pellet gun weapon.

4. First Light Fusion is accelerating a 100 g projectile to about 6.5 km/s velocity in a vacuum. Accelerating something about a third as heavy to about 9 times higher velocity is much harder since the kinetic energy scales as m*v^2, so about (9^2)/3 = 27 times more kinetic energy than the First Light Fusion projectile, and about 3 times more momentum (m*v). You can do the acceleration in a vacuum line, but the projectile will start slowing down and heating up when it hits the atmosphere at 60 km/s.

 

[bcredman]

Now with the double slit experiment, we see zones of interference.

I wonder if that can be true for sonics

https://phys.org/news/2025-02-entangling-physically-resonators-enables-major.html

When light shows interference--have the sonics at their strongest--vice versa---better containment?

Lasers in the news

https://phys.org/news/2025-02-technique-laser-thz-air.html

https://phys.org/news/2025-02-discovery-laser-plasma.html

Negative refraction

https://phys.org/news/2025-02-atomic-arrays-enable-negative-refraction.html

Optics today

https://phys.org/news/2025-02-invisible-electro-optic-cavities.html

https://phys.org/news/2025-02-molecules-circular-3d-displays.html

https://techxplore.com/news/2025-02-recyclable-artificial-vision-honey-electrolyte.html

https://techxplore.com/news/2025-02-electromagnetic-absorber-terahertz-technology-future.html

https://phys.org/news/2025-02-quantum-successfully-particle.html

https://phys.org/news/2025-02-mathematical-solutions-2d-interaction-photonic.html

https://phys.org/news/2025-02-fabrication-method-advances-high-photon.html

https://medicalxpress.com/news/2025-02-high-tech-video-optimization-brain.html

As to your first question, yes sound waves produce interference patterns. All waves of any type produce interference patterns. The sonic device used to guide the spark plasma that we discussed earlier in this thread used the interference pattern from a phased array of acoustic transducers to shape and steer the sonic guiding beam. Similarly, the interference patterns produced by phased arrays of laser emitters or mirrors have been used to shape and steer laser beams.

For your question 'When light shows interference--have the sonics at their strongest--vice versa---better containment?' the answer is probably yes, but using the sound interference pattern to guide the light or visa versa seems like a weaker and more difficult to control effect than just using direct light beam steering using either a steering mirror or an optical phased array, and similarly for the steering of the sonic beam.

Sound quanta, called phonons, have been produced and studied for decades, mostly in crystals. Any type of quanta can be entangled whether its a photon, phonon, electron, neutron, etc. It is inherent in the wave-particle duality of quanta.

The THz steering using the flying focus of a chirped ultrashort pulsed laser is interesting. THz radiation does not propagate very far in the atmosphere. Thus, to do remote sensing with THz illumination, producing the THz radiation at a distance closer to the target location is required. The chirped ultrashort laser pulse focused at some distance produces a plasma source of THz radiation, but previously the direction of the THz radiation was confined to be along the laser beam. Their flying focus technique now allows them to steer the produced THz radiation away from the laser beam axis by controlling the direction and the velocity of the plasma generated at the focus of the laser beam. It is a cool technique, but with a very niche application.

The laser plasma acceleration (LPA) proton source using flowing water as a target is a really cool and unexpected breakthrough with very important applications!