雷射傳耳

https://futurism.com/the-byte/laser-beam-speech-mit?fbclid=IwAR145doPmLmPPAs2lFKqU3kpEUZenUG6ESmJjINLTfM5I-ECZUzURMCBt3U

Both techniques take advantage of something called the photoacoustic effect, which is the formation of sound waves as the result of a material absorbing light. In the case of the MIT research, that material was water vapor in the air. 

For one of their methods, the researchers “swept” a laser beam at the speed of sound, changing the length of the sweeps to encode different audible pitches.

後者就是以光modulate聲音。