acoustic optical modulator (laser) (AOM)

An acousto-optic modulator, Acoustic Optical Modulator(AOM), is an optical component that can be used to control the power and direction of laser beams with an electrical signal. Such a component is based on the acousto-optic effect where the refractive index changes due to the pressure of sound waves.

In terms of construction, an acousto-optic modulator consists of a crystal through which the laser beam is passed and undergoes a delay. A piezoelectric transducer and an absorber are attached to two opposite sides of the crystal. An acoustic signal with a frequency of 100 MHz is fed into the crystal via the transducer.

Structure of an acousto-optic modulator (AOM)

Due to the generated and propagating sound oscillation, the laser beam experiences a refraction which deflects it in its direction. Because of this effect, corresponding components are also called Bragg cells. Depending on the tone frequency and the propagation direction of the acoustic signal, the optical frequency of the light scattering increases or decreases, propagating in different directions.

AOM modulators are used in acoustic-optical Q-switches, to modulate the power of a laser beam, for example in printers, to change the frequency of laser beams or its diffraction.