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Laser Crystals and Components

Electro-Optic (EO) Crystals and Acousto-Optic (AO) Crystals

Electro-optic crystals are crystals which demonstrate a certain linear(Pockels Effect) or non linear electro-optic effect( Kerr Effect) . In Pockels Effect the refractive index of the crystals is changed in proportion to the magnitude of the electric field applied to it, those that change in proportion to the square of the external electric field is called the secondary electro-optic effect or Kerr effect. Although the change in refrative indices introduced by electric field is minute, it is enough to cause the characteristics of light propagation in the crystal to change, so that the mutual conversion of opto-electronic signals and mutual modulation can be achieved through changes in the external field. These crystals are particularly for electro-optic modulators (EOM) which are used to control the intensity (intensity modulators), phase(phase modulatiors) or polarization of light. The operation of the modulators are based on the linear EO effect (Pockels Effect).

Hangzhou Shalom EO offers the off-the-shelf and custom electro-optic and acousto-optic crystals for EO and AO  modulations and pockels cells, they are made from high quality crystals with high precision polishing, coatings and Cr-Au electrode, a variety of substrate materials are available: DKDP, BBO, LiNbO3, MgO:LiNbO3, TeO2 and HGTR-KTP crystals.Shalom EO also offers the stocked and custom DKDP, BBO and LiNbO3 / MgO:LiNbO3 Pockels Cells.

DKDP: It has the advantages of low half-wave voltage, large linear electro-optic coefficient, wide transmission band, and good optical honmogeneity. However it is hydroscopic.

LiTaO3: The tansverse electro-optic modulation of the crystal can be used to measure the electric field. LiTaO3 has higher electro-optical coefficient than LiNbO3, high optical damage threshold , low birefringence ,and high light transmittance.

LiNbO3: It has relatively low half wave voltage and stable physical/chemical poperties ,suitable for solid state lasers with low-medium frequency. 

BBO: It is the best choice for high power applications and high repetition DPSS Q-switching for their superior damage threshold and wide transparency range .However it requires high voltages.

KTP: It has high electro-optic coefficients and low dielectric constant, being capable of operations of high repetition rate.

Comparatively, acousto-optic effects are based on the change of the refractive index of a medium due to the presence of sound waves in that medium, and Tellurium Dioxide (TeO2) crystals one of the most popular acousto-optic crystals used in laser applications due to its its large elasto-optic coefficient and high refractive index, and it is the most widely used crystal.