[Physics] Can a soap bubble bounce off a laser

bubbleselectromagnetismlaseropticsthermodynamics

Clip; I presume some momentum transfer's at play, but can't put a full picture together. What's going on – why does the laser 'repel' the bubble? … or is it fake?

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This was faked by using a fishing reel /invisible string to invisibly guide the bubble. It is discussed in detail in this video and this video by Seb Lee and Steve Mould.

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[Physics] Why is light produced when an underwater bubble is collapsed with a sound wave

There is a detailed review of this phenomenon here

The phenomenon is known as sonoluminescence. One of the leading theories is that it is caused by "adiabatic heating of the bubble at collapse, leading to partial ionization of the gas inside the bubble and to thermal emission such as bremsstrahlung."

[Physics] Could you use a laser beam as a modulated carrier wave for radio signal

It's definitely possible to modulate a laser beam to carry radio frequency signals, using any of several different methods. Amplitude modulation, frequency modulation, and phase modulation are all easy. An Acousto-Optic modulator can be used to modulate either amplitude or frequency at radio frequencies. Many decades ago I designed (and a friend built) a laser transmitter-receiver system that simply bounced a collimated laser beam off an aluminized Mylar film stretched across a small speaker cone. An audio signal fed to the speaker caused a "drumhead" deflection of the film, which distorted the reflected wavefront, causing slight deviations from collimation. At a distance, this resulted in amplitude modulation of the beam's brightness- easily detected using a photodiode.

The frequency of a laser is directly related to its cavity length, defined by the distance between its two mirrors. A piezoelectric crystal is easily used to drive one of the mirrors and thereby modulate the laser frequency.

The most direct way to modulate a laser beam at radio frequencies might be an electro-optic modulator. A Pockels cell can modulate at up to about 100 kHz. A Kerr cell can modulate at up to about 10 GHz. An acousto-optic modulator can modulate at up to about 200 MHz.

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[Physics] Why is light produced when an underwater bubble is collapsed with a sound wave

[Physics] Could you use a laser beam as a modulated carrier wave for radio signal

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