What is the principle of acousto-optic modulator?

What is the principle of acousto-optic modulator?

How Does an Acousto-Optic Modulator Work? Acousto-optic modulator typically uses a transparent crystal or piece of glass as a medium for light propagation. An electric signal then drives an attached transducer to vibrate, therefore generating a sound wave within the cell.

What are acousto-optic devices?

Acousto-optics is a versatile technology that allows users to precisely and rapidly control the wavelength, amplitude and propagation direction of a laser beam. These capabilities are proving popular in applications as diverse as agriculture, entertainment and defence.

Which is true about acousto-optic modulator?

Acousto-optic modulators are much faster than typical mechanical devices such as tiltable mirrors. The time it takes an AOM to shift the exiting beam in is roughly limited to the transit time of the sound wave across the beam (typically 5 to 100 ns). When faster control is necessary electro-optic modulators are used.

What is acousto-optic effect?

The acousto-optics is a field of physics that studies the interaction between sound and light. This interaction effect based on the diffraction of light by periodic modulation of the refractive index of a transparent optical material, which is generated by acoustic wave propagation in that environment.

How does an acousto-optic deflector work?

Acousto-optic deflectors are devices which can be used to deflect a laser beam in one direction by a variable angle, controlled by the frequency of an electrical signal. Essentially, such a device is an acousto-optic modulator which is operated with an electrical drive signal of constant power but a variable frequency.

What is Raman Nath effect?

Raman–Nath diffraction is observed with relatively low acoustic frequencies, typically less than 10 MHz, and with a small acousto-optic interaction length, ℓ, which is typically less than 1 cm. This type of diffraction occurs at an arbitrary angle of incidence, .

What is Raman-Nath theory?

At sound frequencies of a few megahertz and lower, Raman-Nath theory determines light diffraction by sound if the interaction length is no longer than about 35 cm. Imaging rules under Raman-Nath conditions are nearly the same as corresponding rules for imaging under Bragg conditions.

What is acousto-optic tunable filter?

The acousto-optic tunable filter (AOTF) is an electro-optical device that functions as an electronically tunable excitation filter to simultaneously modulate the intensity and wavelength of multiple laser lines from one or more sources.

What is electro optic crystal?

Electro-optical Crystals has been widely used for electro-optic modulators and electro-optic deflectors. In service section, we give a specific example of polarization scrambler. It consists of two variable wave plates orientated at a 45 azimuth with each other. Each wave pate has a maximum phase retardation of 2π.

How does an AOM work?

An acousto-optic modulator (AOM) is a device which can be used for controlling the power of a laser beam with an electrical drive signal. A transducer generates a sound wave, at which a light beam is partially diffracted. The diffraction angle is exaggerated; it is normally only of the order of 1°.

What is acousto Crystal?

Acousto-optics is a branch of physics that studies the interactions between sound waves and light waves, especially the diffraction of laser light by ultrasound (or sound in general) through an ultrasonic grating.

What are the characteristics of acoustical waves?

Acoustic waves are mechanical and longitudinal waves (same direction of vibration as the direction of propagation) that result from an oscillation of pressure that travels through a solid, liquid or gas in a wave pattern. These waves show numerous characteristics including wavelength, frequency, period and amplitude.

How are acousto optic modulators used in lasers?

An acousto-optic modulator (AOM), also called a Bragg cell, uses the acousto-optic effect to diffract and shift the frequency of light using sound waves (usually at radio-frequency). They are used in lasers for Q-switching, telecommunications for signal modulation, and in spectroscopy for frequency control.

What are the basic principles of acousto optic?

This website is made to help user to understand basic principles of acousto-optic theory, on which acousto-optic devices are based on. A.A is a world leader in the manufacturing of quality Acousto-optic and radio frequency devices.

Which is faster acousto optic modulator or tiltable mirror?

Acousto-optic modulators are much faster than typical mechanical devices such as tiltable mirrors. The time it takes an AOM to shift the exiting beam in is roughly limited to the transit time of the sound wave across the beam (typically 5 to 100 ns ). This is fast enough to create active modelocking in an ultrafast laser.

How big is the angular deflection of acousto-optic modulator?

In thick crystals with weak modulation, only phasematched orders are diffracted; this is called Bragg diffraction. The angular deflection can range from 1 to 5000 beam widths (the number of resolvable spots). Consequently, the deflection is typically limited to tens of milliradians .