The Yttrium Orthovanadate (YVO4) is a positive uniaxial crystal grown with Czochralski method. It has good mechanical and physical properties and is ideal for optical polarizing components because of its wide transparency range and large birefringence. It is an excellent synthetic substitute for Calcite (CaCO3) and Rutile (TiO2) crystals in many applications including fiber optic isolators and circulators, beam displacers, Glan polarizers and other polarizing optics, etc.
Main properties of YVO4 crystal
| Crystal Symmetry | Zircon Tetragonal, Space Group D4h |
| Transmittance Range | 400-5000nm |
| Crystal Cell | a=b=7.12Å, c=6.29Å |
| Density | 4.22g/cm3 |
| Mohs Hardness | 5 |
| Hygroscopic Susceptibility | None |
| Thermal Expansion Coefficient | αa=4.43×10-6/K αc=11.37×10-6/K |
Themal Optical Coefficient | ∥c:5.23 W/m/K, ⊥c:5.10 W/m/K |
| dna/dT=8.5x10-6/K | |
| Refractive Indices, Birefringence (Δn=ne-no) and Walk-off Angle at 45°(ρ) | n0=1.9500 ne=2.1554 Δn=0.2054 ρ=5.72°@1300nm |
| n0=1.9447 ne=2.1486 Δn=0.2039 ρ=5.69° @1550nm | |
| Sellmeier Equations (λ in μm) | no2=3.77834+0.069736/(λ2-0.04724)-0.0108133λ2 |
| ne2=4.59905+0.110534/(λ2-0.04813)-0.0122676λ2 |
Specifications of YVO4 Beam displacers
| Dimensional Tolerances | W(±0.05mm)xH(±0.05mm)xL(±0.1mm) |
| Flatness | ＜λ/10@632.8nm |
| Wavefront Distortion | ＜λ/8@632.8nm |
| Parallelism | ≤10" |
| Perpendicularity | ≤5" |
| Surface Quality | 10-5 S/D |
| Acurracy of Oriention | ≤0.5° |
| AR-coating | R<0.2%@1550+/-40nm or 1310+/-40nm |
Calcite is a negative uniaxial crystal that has high birefringence, wide spectral transmission and availability in reasonably sized rhombs. Although a fairly soft crystal and easily scratched, Calcite is an ideal material for use as visible wavelengths and near IR polarizers such as Glan Taylor, Glan Thompson and Glan Laser.
Main Properties of Calcite Crystal
| Transmittance Range | 350-2300nm |
| Density | 2.7g/cm3 |
| Mohs Hardness | 3 |
| Hygroscopic Susceptibility | Low |
| Thermal Expansion Coefficient | αa=24.39×10-6/K αc=5.68×10-6/K |
| Crystal Class | Negative uniaxial with no=na=nb, ne=nc |
Refractive Indices, Birefringence (Δn=ne-no) and Walk-off Angle at 45°(ρ) | n0=1.6629 ne=1.4885 Δn=-0.1744 ρ=6.32° @630nm |
| n0=1.6557 ne=1.4852 Δn=-0.1705 ρ=6.20° @1300nm | |
Sellmeier Equations (λ in μm) | no2=2.69705+0.0192064/(λ2-0.001829)-0.0151624λ2 |
| ne2=218438+0.0087309/(λ2-0.01018)-0.0024411λ2 |
Specifications of Polarizers
| Dimensional Tolerances | +/-0.1mm |
| Flatness | ＜λ/4@632.8nm |
| Surface Quality | 10-5 S/D |
| Acurracy of Oriention | ≤0.5° |
| Beam Deviation | <3' |
| AR-coating | Single MgF2 |
High temperature form of BBO (α-BaB2O4) is a negative uniaxial crystal. It has large birefringence over a broad transparent range of 190nm to 3500nm. The physical, chemical, thermal and optical properties of α-BBO are similar to those of β-BBO. However, the nonlinear optical properties of a-BBO crystals are nonexistent due to the centric symmetry with its crystal structure. α-BBO crystal is not recommended for NLO processes.
Main Properties of Calcite Crystal
| Transmittance Range | 190-3500nm |
| Density | 3.85g/cm³ |
| Mohs Hardness | 4.5 |
| Hygroscopic Susceptibility | Low |
| Thermal Expansion Coefficient | αa=4×10-6/K αc=36×10-6/K |
| Optical Homogeneity | Δn=10-6/cm |
| Linear Absorbtion Coefficient | 0.05%/cm-1@300-2300nm |
Themal Optical Coefficient | dno/dT=-9.3x10-6/K |
| dne/dT=-16.6x10-6/K | |
| Damage Threshold | 1 GW/cm2 @1064nm, 500 MW/cm2 @532nm |
| Refractive Indices, Birefringence (Δn=ne-no) and Walk-off Angle at 45°(ρ) | no=1.7617 ne=1.6719 Δn=-0.0898 ρ=-5.6926° @266nm |
| no=1.6776 ne=1.6021 Δn=-0.0755 ρ=-5.0407° @532nm | |
| no=1.6579 ne=1.5846 Δn=-0.0733 ρ=-4.953° @1064nm |
Specifications of YVO4, α-BBO and Calcite Polarizers
LiNbO3 (LN) crystal is widely used as frequency doublers for wavelength greater than 1000µm and optical parametric oscillators (OPOs) pumped at 1064 nm and quasi-phase-matched (QPM) devices. Due to its unique electro-optical, photoelastic, piezoelectric and non-linear properties, Lithium Niobate is widely used in a variety of integrated and active acousto-optical devices. The material is Czochralsky grown and poled along Z-axis.
Main Properties of LN Crystal
| Crystal Structure | Trigonal, Space Group R3c, Point group 3m |
| Transmittance Range | 420-5200nm |
| Absorption Coefficient | ~0.1%/cm at 1064nm |
| Melting Point | 1253ºC |
| Density | 4.64g/cm3 |
| Mohs Hardness | 5 |
| Hygroscopic Susceptibility | None |
| Thermal Conductivity Coefficient | 38 W/m/K at 25ºC |
| Thermal Expansion Coefficient (at 25ºC) | ∥a:2.0×10-6/K, ∥c:2.2×10-6/K |
| Themal Optical Coefficient | dno/dT=-0.874x10-6/K at 1.4μm |
| dne/dT=39.073x10-6/K at 1.4μm | |
| Refractive Indices | n0=2.232 ne=2.156 @1064nm |
| n0=2.220 ne=2.146 @1300nm | |
| Sellmeier Equations (λ in μm) | no2=4.9048+0.11768/(λ2-0.004750)-0.027169λ2 |
| ne2=4.5820+0.099169/(λ2-0.04443)-0.021950λ2 |
Specifications of LN Wedges
| Dimensional Tolerances | +/-0.05mm |
| Flatness | ＜λ/10@632.8nm |
| Parallelism | ≤10" |
| Perpendicularity | ≤5" |
| Surface Quality | 10-5 S/D |
| Acurracy of Oriention | ≤0.5° |
| Wedge Angle Tolerances | +/-0.1° |
| AR-coating | R<0.2%@1550+/-40nm |
