Acoustic optic Modulator

Elkay Electromech > Products & Services > Components > Acoustic optic Modulator
Posted by: Web Admin July 13, 2020 No Comments


An acousto-optic modulator is made to vary the intensity of the incoming laser beam (Amplitude Modulation, AM). The modulation can be digital (ON/OFF) or analog (sine, square, linear, random…).

The key parameter of a modulator is its rise/fall time, which defines the achievable « speed » of the modulation, or amplitude modulation bandwidth. The rise/fall time is proportional to the beam diameter inside the modulator. As a consequence, the laser beam must be focused inside the modulator to reach a fast rise time.

Fixed Frequency Shifters:

An acousto-optic frequency shifter uses the frequency shift of the laser beam inherent to the acousto-optic interaction. The laser wavelength is frequency shifted by the amount of the carrier RF frequency. The frequency shift can be positive or negative, depending on the angular sketch configuration. Modulators are used as fixed frequency shifters.

Acousto-Optic AOTF Tunable Filters

An AOTF is a solid-state, electronically Tunable Bandpass filter, which uses the acousto-optic interaction inside an anisotropic medium. These filters can be used with multi-lines sources (mixed gas lasers, Laser diodes…) or with broadband light sources (Xenon, Halogen lamps…). They allow to select and transmit a single or multiple wavelengths from the incoming light.