Yttrium Vanadate(YVO4) is a positive uniaxial crystal grown with Czochralski method. It has good temperature stability and physical and mechanical properties. It 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, interleavers, beam displacers and other polarizing optics ( refer to Table 1).
Table 1.Comparison of basic properties between YVO4 and Other Birefringent Crystals.
YVO4 | TiO2 | CaCO3 | LiNbO3 | ||
Thermal Expansion (/℃) | c-axis | 11.4x10-6 | 9.2x10-6 | 26.3x10-6 | 16.7x10-6 |
a-axis | 4.4x10-6 | 7.1x10-6 | 5.4x10-6 | 7x10-6 | |
Refractive Index | no | 1.9447@1550nm | 2.454@1530nm | 1.6346@1497nm | 2.2151@1440nm |
ne | 2.1486@1550nm | 2.710@1530nm | 1.4774@1497nm | 2.1413@1440nm | |
Birefringence(ne-no) | 0.2039@1550nm | 0.256@1530nm | -0.1572@1497nm | -0.0738@1440nm | |
Mohs Hardness | 5 | 6.5 | 3 | 5 | |
Deliquescence | None | None | Weak | None | |
Transparency range | 0.4-5μm | 0.4-5μm | 0.35-2.3μm | 0.4-5μm | |
Basic Properties of YVO4 crystal
Transparency Range: | High transmittance from 0.4 to 5 μm |
Crystal Symmetry: | Zircon Tetragonal, space group D4h |
crystal Cell: | a=b=7.12A;c=6.29A |
Density: | 4.22 g/cm3 |
Mohs Hardness: | 5, glass-like |
Hygroscopic Susceptibility: | Non-hygroscopic |
Thermal Expansion Coefficiet: | αa=4.43x10-6/K;αc=11.37x10-6/K |
Thermal Conductivity Coefficient: | //C:5.23 W/m/K;⊥C:5.10 W/m/K |
Crystal Class: | Positive uniaxial with no=na=nb,ne=nc |
Thermal Optical Coefficient: | Dna/dT=8.5x10-6/K;dnc/dT=3.0x10-6/K |
Refractive Indices, Birefringence (△n=ne-no) and Walk-off Angle at 45°(ρ): | no=1.9929,ne=2.2154,△n=0.2225,ρ=6.04° at 630nm |
Sellmeier Equation (λ in μm): | no2=3.77834+0.069736/(λ2-0.04724)-0.0108133λ2ne2=4.59905+0.110534/(λ2-0.04813)-0.0122676λ2 |
YVO4 crystal application
YVO4 crystal are widely used in fiber-optic isolators,beam displacers for fiber optical circulators, and interleavers, etc.
1.Specifications of birefringent wedges for fiber-optic isolators
Aperture | 1.0x 1.0mm2 to 4x4mm2 | ||
Dimension tolerance | +/-0.05mm | ||
Wedge Angle tolerance | +/-0.1° | ||
Optical axis orientation | +/-0.5° | ||
Flatness | λ/4 @ 632.8 nm | ||
Surface Quality | 20-10 | ||
AR-coating | R<0.2% @1550 or 1310nm | ||
Standard Size | 1.25mmx1.25mmx0.5mm with 13° or 15° wedge, phi=22.5° | ||
2. Specifications of YVO4 beam displacers for fiber-optic circulators orinterleaver | |||
Dimension tolerance | W(+/-0.05mm)xH(+/-0.05mm)xL(+/-0.1mm) | ||
Optical axis orientation | +/-0.5° | ||
Parallelism | <15 arc sec | ||
Perpendicularity | <10 arc min | ||
Flatness | λ/4 @ 632.8nm | ||
Surface Quality | 20/10 | ||
AR-coating | R<0.2% @1550 or 1310nm +/-40nm | ||
Standard Size | 2.6x2.6x10mm, θ=45°,Φ=0° Other sizes and specifications are available upon request | ||
