Acousto-optic modulator

<p>An acousto-optic modulator (AOM), also called a Bragg cell or an acousto-optic deflector (AOD), uses the <a href="/facts/Acousto-optic_effect/mlSxzC7m">acousto-optic effect</a> to <a href="/facts/Diffraction/Mk80xXHT">diffract</a> and shift the frequency of light using <a href="/facts/Sound_wave/DlKXlPuF">sound waves</a> (usually at <a href="/facts/Radio-frequency/aWku7h4R">radio-frequency</a>).  They are used in <a href="/facts/Laser/jk6PTvvT">lasers</a> for <a href="/facts/Q-switching/BNVh2d4N">Q-switching</a>, telecommunications for signal <a href="/facts/Modulation/aAXPjINv">modulation</a>, and in <a href="/facts/Spectroscopy/mj71FuNK">spectroscopy</a> for frequency control.  A <a href="/facts/Piezoelectric_transducer/65k6BDqx">piezoelectric transducer</a> is attached to a material such as glass. An oscillating electric signal drives the transducer to vibrate, which creates sound waves in the material.  These can be thought of as moving periodic planes of expansion and compression that change the <a href="/facts/Index_of_refraction/yjkzvgeE">index of refraction</a>.  Incoming light scatters (see <a href="/facts/Brillouin_scattering/bnCg0jDW">Brillouin scattering</a>) off the resulting periodic index modulation and interference occurs similar to <a href="/facts/Bragg_diffraction/qEYANzQg">Bragg diffraction</a>.  The interaction can be thought of as a three-wave mixing process resulting in <a href="/facts/Sum-frequency_generation/0mPKGhN3">sum-frequency generation</a> or <a href="/facts/Difference-frequency_generation/0sRq9zld">difference-frequency generation</a> between <a href="/facts/Phonon/tflWW6vw">phonons</a> and <a href="/facts/Photon/mFNhAEzA">photons</a>.
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Acousto-optic modulator open-in-new

Acousto-optic modulator