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Laser Components Pockel Cell LiNbO3 Pockel Cell
Electro-optic Pockels cells are used in applications that require fast switching of the polarization direction of a beam of light. These uses include Q-switching of laser cavities, coupling light into and out from regenerative amplifiers, and, when used in conjunction with a pair of polarizers, light intensity modulation. Pockels cells are characterized by fast response, since the Pockels Effect is largely an electronic effect that produces a linear change in refractive index when an electric field is applied, and they are much faster in response than devices based on acoustic changes in a material.
Although Pockels cells can be used for phase modulation, during which sidebands are imprinted onto the frequency of the transmitted light at multiples
of the drive frequency of the Pockels cell, these cells are not as efficient as devices that use an optimal crystal orientation and electric field direction and are designed specifically as phase modulators.
Selection of the best crystalline material to use as the Pockels cell medium is determined by the wavelength of operation and the specific performance requirements such as damage threshold, average power handling ability, contrast ratio, extinction ratio, and repetition rate.
LiNbO3 Pockels cells use a configuration in which the electric field is applied transverse to the direction of light propagation. This configuration allows lower voltages to be used for a given retardance through the use of thinner and longer crystals. Hard, damage resistant, anti-reflective coatings are deposited directly on the polished crystal faces in order to reduce reflective losses. For work at repetition rates above 100 Hz, a piezoelectrically damped version can be used.
This capacitive Pockels cell uses standard 9mm xm 9mm x 25 mm crystals that have found widespread use in military and medical laser systems. Standard AR coatings at 1064 nm make this a versatile unit. Transmission of the 1064 nm

LiNbO3 Pockels Cell Specifications:

Aperture Diameter 8.5 mm
Repetition Ratio <1000Hz
Quarter-Wave Voltage 1.65Kv
Intrinsic Contrast
@ 1064 nm
> 300 : 1
Optical Transmission > 98 % T
Damage Threshold*
(Nanosecond Pulses)
> 200 MW / cm2
Damage Threshold*
(cw Power)
> 1 kW / cm2
Wavefront Distortion
@ 1064 nm
< l/4
Electrical Contacts two, electrically floating, miniature banana plugs
Typical Capacitance 20 pF
Outline Dimensions 1" Diameter x 2" Long Cylinder

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