Laser Crystals and Components
Electro-optic Crystals (EO Crystals) are crystals that demonstrate a certain linear electro-optic effect called the Pockels Effect. In the Pockels Effect, when an external electric field is applied to the electro-optic crystal, the refractive indices of the crystals are changed in proportion to the magnitude of the electric field. Although the change in refractive indices introduced by the electric field is minute, it is enough to cause the characteristics of light propagation in the crystal to change, so that mutual conversion of electro-optic signals and modification of light can be achieved. EO crystals are oriented for manufacturing electro-optic modulators (EOM) which are used to control the amplitude (amplitude modulators), phase (phase modulation), or the polarization state of light. And E-O modulations could be divided into longitudinal EO modulation in which the directions of electric field and light propagation are the same and transverse EO modulation in which the directions of electric field and light propagation are orthogonal. KDP crystals are often used in the longitudinal scheme, whilst LiNbO3, MgO:LiNbO3, ZnO:LiNbO3, BBO, and KTP crystals are often used in the transverse scheme.
Acousto-optic Crystals (AO Crystals) are crystals that exhibit the Acousto-optic effect, which is a phenomenon based on the change in refractive index of a medium due to the presence of sound waves in the medium. By interaction between the refractive characteristic of the material and the oscillating mechanical strain, the sound waves then create a diffraction grating in the crystal. AO crystals are often assembled with an acoustic absorber and a piezoelectric transducer to compose an acousto-optic modulator (AOM), which can be utilized for manipulating the transmitted power of a laser beam with an electrical drive signal.
Hangzhou Shalom EO offers off-the-shelf and custom electro-optic and acousto-optic crystals for EO and AO modulations and pockels cells. The crystals feature rich dimension/orientation options, large apertures, while also boasting high-precision polishing, and different kinds of coatings, Cr-Au electrodes can be furnished. various substrate materials are available: DKDP, BBO, LiNbO3, MgO:LiNbO3, TeO2, and HGTR-KTP crystals. Crystals could be offered in the forms of crystal boules, crystal blanks, and crystals with AR coatings and electrodes. Shalom EO also offers stocked and custom DKDP, BBO, and LiNbO3 / MgO:LiNbO3 Pockels Cells.
Below is a brief selection guide:
DKDP: It has the advantages of low half-wave voltage, large linear electro-optic coefficient, wide transmission band, and good optical homogeneity. However, it is hygroscopic.
LiTaO3: LiTaO3 has a higher electro-optical coefficient than LiNbO3, a high optical damage threshold, low birefringence, and high light transmittance.
LiNbO3: It has low half-wave voltage and stable physical/chemical properties, suitable for solid-state lasers with low-to-medium frequencies.
BBO: It is the best choice for high-power applications and high repetition DPSS Q-switching due to its superior damage threshold and wide optical transmission wavelength range. However, it requires high voltages.
KTP: It has high electro-optic coefficients and low dielectric constant, being capable of operations with a high repetition rate.
TeO2: Tellurium Dioxide (TeO2) crystals are one of the most popular acousto-optic crystals used in laser applications due to their large elastic-optic coefficient and high refractive index.
