Home Discussion Forum Can sound waves interere with light waves?

Can sound waves interere with light waves?

Please give a answer that addresses the molecular level in an understandable language(don’t know much about quantum mechanics)


  1. I would say that pressure waves in air could indeed affect light.
    light travels at different speeds through ddiffernt substances. WIth air the light can be bent if the pressure varies. Example: on a hot day you look at the ground and everything looks squiggly moviving. It may even look like the ground is wet. This is due to the light bending because of the decrease in air pressure near the hot ground.
    The light will be bent if the pressure varies engough. SInce sound is a compression wave through air i would think that an intense enought sound could ben light

  2. Yes, sound waves do influence the path of light, however it is not strictly a form of interference.
    One way that sound can influence the path of light is due to the fact that you get some places that have higher pressure than others. As the light travels through the high pressure regions the index of refraction of the air is higher there. This change in the index of refraction is similar to what you get with lenses, so when you have sound, you have lots of little, relatively weak lenses.

  3. Yes. The acousto-optic effect relates mechanical strain and refractive index – acoustic waves alter the strain with position, which in turn alters the refractive index with position. Because sound is also a wave, the index variation is periodic – if you’re familiar with electrodynamics, a periodic refractive index variation creates a diffraction grating.
    This is not prominent in all materials due to the parameters involved if you go through and derive the equations. A few well-known materials with decent responses are used as acousto-optic modulators, for example. Use of the acousto-optic effect allows faster switching than typical mechanical modulator elements like mirrors.


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