Fun fact, it was invented by Leon Theremin. The inventor of the Theremin.

the words you use matter.

Here's what Theremin invented: https://en.wikipedia.org/wiki/The_Thing_(listening_device)

Radio waves are light. By definition, they are optical wavelengths.

For example, the company I work for manufactures DUV optics for the semiconductor industry and IR optics for the defense industry.

https://en.wikipedia.org/wiki/Optics "Optics usually describes the behaviour of visible, ultraviolet, and infrared light."

https://en.wikipedia.org/wiki/Radio_wave "Radio waves are a type of electromagnetic radiation with the lowest frequencies and the longest wavelengths in the electromagnetic spectrum, typically with frequencies below 300 GHz and wavelengths greater than 1 mm"

I see no problem with using the term 'optical wavelength' to distinguish between a wavelength of ~1 micrometer and 'radio waves' at ~1 meter.

> The study of optics extends to other forms of electromagnetic radiation, including radio waves, microwaves, and X-rays.

I have no problem with this usage if the distinction helps understanding, but we seem to be discussing terms with multiple conflicting definitions without defining them: laser, light, radio, optics. All of these can reasonably apply to MHz radiation!

No one disputes that 'optics' can refer to more than visible light. But, in the context of a discussion about lasers and 1950's radio devices operating at VHF, we can still use terms like 'optical wavelength', 'radio wave', 'light', etc to distinguish the phenomena.

Language is a two-way street. Words are imprecise tools for people who want to communicate together, even in engineering and physics. Being pedantic without a deeper point to make isn't a useful contribution.

> Yes, he invented the technique of monitoring audio through light. How was I wrong there?

> These radio waves have a wavelength of about a meter, which is about 6 orders of magnitude longer than an optical wavelength.

> The point was light being used for audio, not specifically laser as a light source.

> You seem to keep responding to multiple people defend your point, but he used 1320 MHz in the thing which is not light.

These comments disagree on important definitions. I don't think it's pedantic to point this out.

There are three approximate frequency bands being discussed. The bands are separated by a factor of about 1 million. The width of each band is a factor of 3-8.

Human voice audio - 500 Hz to 4 kHz (the modulating signal)

VHF-UHF radio - 330 MHz and 1320 MHz

"Light" - 300 to 800 THz

This is an arbitrary restriction to the visible. (Note that the first person to mention the word "visible" was you!)

The original comment (ClikeX) clearly included radio waves in their intent, and that is an accepted definition! It's the definition I see used in practice as an optical engineer.

ClikeX originally claimed that the USSR had lasers in 1945 (untrue) and that Leon Theremin invented the detection of sound vibrations or audio reproduction of via light (also untrue).

The confusion here is between the two different eavesdropping systems developed by Theremin: The Buran eavesdropping system (which used likely-near infrared on windowpanes) and "The Thing" (which used VHF-UHF radio on a custom device).

Your repeated insistence on the unrelated point that "light" and "radio" are technically both electromagnetic waves isn't clarifying anything.

I'm quite confident it was an optical wavelength! ;)

> ClikeX originally claimed that the USSR had lasers in 1945 (untrue) and that Leon Theremin invented the detection of sound vibrations or audio reproduction of via light (also untrue).

> The confusion here is between the two different eavesdropping systems developed by Theremin: The Buran eavesdropping system (which used likely-near infrared on windowpanes) and "The Thing" (which used VHF-UHF radio on a custom device).

Great summary!

> Your repeated insistence on the unrelated point that "light" and "radio" are technically both electromagnetic waves isn't clarifying anything.

I hope it's helped clarify that of the terms used here (light, radio, and electromagnetic waves) only "radio" is clearly distinct as "light" and "electromagnetic waves" are often synonyms.

> Apparently happy with ‘the thing’, Beria called on Theremin’s services again and he was enlisted for further eavesdropping operations. In 1947 or earlier, when Theremin probably served in the Kuchino sharashka outside Moscow, he was called upon to create another device for wireless surveillance, but this time it should operate fully remotely without any device planted at the target site. The project received the code name buran (snowstorm). To solve this difficult task, Theremin paid attention to the resonators already present in a building, such as windows. A conversation in a room may cause window panes to vibrate slightly, and Theremin devised a method to detect these vibrations from a distance, using an infrared beam directed at the window pane, and then to interpret them and convert them to discernible speech (Glinsky, 2005, p.261).

>

> The buran was able to detect speech from as far away as 500 metres, making detection very difficult. Interception would have to disrupt the infrared beam and jamming would require optical overpowering. Both were unlikely. However, it could be used only when weather permitted and was not effective in rain, fog or smog (Glinsky, 2005, p.261). Buran is often considered a predecessor of the laser microphone, although it employed an infrared beam rather than laser.

https://www.jstor.org/stable/10.2307/48828289

they track BUTTERFLIES from Canada to Mexico by attaching tiny trackers with eyelash glue

* https://celltracktech.com/products/ctt-blumorpho

smaller than a tic-tac candy (about two match-heads)

* https://cellular-tracking-technologies.github.io/ctt_documen...

It's been some time since I've thought about Van Eck phreaking: https://en.wikipedia.org/wiki/Van_Eck_phreaking