Visible Light Electronic Apertures ?

[Kryptid]

This is mostly a question in regards to possibilities, not practicalities.

AESAs are able to form, focus, and direct beams of radio waves based on constructive and destructive interference. Could the same be done with visible light instead of radio waves? Like, could a flashlight be made that could change the direction of its light beam based on the same principle that an AESA uses to direct its beams (i.e. no mechanical means needed)?

 

[mz]

Warning, I'm not well versed in radar technology.

Phased arrays for light:

AFAIK matter can not be manipulated well enough at that level at least not yet. Since atoms are sub-nanometer structures, maybe some structures could work in the hundreds nanometers that is visible light.
Microprocessor line width is 45 nm at the moment?

AFAIK, at the moment the phase of light emitted by light producing devices is not very well controlled, so it's hard to do constructive or destructive interference.
Since the wavelength in visible is on the order 100 nm and not 100 mm like in radar, the timing needs to be a million times more precise.

The same problem with sensing as well - you need physical beam combining for things like interferometry (lenses, mirrors, prisms), you can't have telescopes around the world just doing measurements, digitizing them and sending over the internet like you, AFAIK, can do with radio telescopes nowadays. Because a precise enough phase or time of arrival of the light is not stored by the sensors.

I don't know what's the status with something like Terahertz devices right now that sit already closer to optical. They're a new technology and I presume the antennas are quite weird.

Photoconductive Antenna for terahertz waves (PCA)

I guess if you just put these in an array, you'd get it:

Single photon emitter | Boing Boing

Researchers at the University of Southern California are building a “quantum emitter” that uses just one electron to generate a single photon signal. Combined with a suitable detector, …

www.boingboing.net

Except you probably couldn't time them accurately enough anyway.