YVO4
YVO4
The yttrium orthovanadate (YVO4) is a positive uniaxial crystal grown with Czochralski method. It has good temperature stability and physical and mechanical properties, wide transparency and large birefringence, so it is also ideal for optical components such as fiber optical isolators and circulators, beam displaces and other polarizing optics, etc.
It is well known that YVO4 crystal growth and fabrication are much easier than that of TiO2 (too high hardness) and CaCO3 crystals (easy cleavage and its susceptibility to moisture), so its price is very competitive compared to that of other similar crystals. Accordingly, it is much more practical than TiO2 and CaCO3 crystals. Since high optical quality YVO4 crystal is available easily in large quantities, it is substituting step by step TiO2 and CaCO3 crystal as relevant optical components.
Basic Properties of YVO4 Crystals
| Transparency Range high transmittance from 0.4 to 5mm | Transparency Curve of YVO4(Thickness=1mm) |
| Crystal Symmetry Zircon Tetragonal, space group D4h | |
| Crystal Cell a=b=7.12Å; c=6.29 Å | |
| Density: 4.22 g/cm3 | |
| Hygroscopic Susceptibility: Non-hygroscopic | |
| Thermal Expansion Coefficient aa = 4.43 x 10-6/K; ac = 11.37 x 10-6/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 | |
| Refractive Indices, Birefringence (Dn = ne - no) and Walk-off Angle at 45º (r): no = 1. 9929, ne = 2.2154, Dn = 0.2225, r = 6.04º at 633nm no = 1.9500, ne = 2.1554, Dn = 0.2054, r = 5.72º at 1.30 mm no = 1.9447, ne = 2.1486, Dn = 0.2039, r = 5.69º at 1.55 mm | |
| Sellmeier Equation (l in mm): no2= 3.77834 + 0.069736/(l2 - 0.04724) - 0.0108133l2 ne2=4.59905 + 0.110534/(l2 - 0.04813) - 0.0122676l2 | |
| Thermal Optical Coefficient: dna/dT = 8.5x10-6/K; dnc/dT = 3.0x10-6/K | |
Comparation with other Birefringent crystals
Compared to Calcite, YVO4 has better temperature stability and physical and mechnical properties. Calcite is hard to obtain high optical quality because of its low susceptibility to moisture and low hardness.
Compared to Rutile (TiO2) which exhibits too high hardness, YVO4 is easier to be handled for optical surface processing that greatly reduces cost of fabrication, especially for batch production.
Compared to LiNbO3, although they have similar mechanical and physical properties, YVO4 has more than three times larger birefringence, that makes your design more compact.
| YVO4 | TiO2 | CaCO3 | LiNbO3 | ||
Thermal Expansion( /Co) | 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 | 2x10-6 | |
| Refractive Index | no | 1.9447 (at 1550nm) | 2.454 (at 1530nm) | 1.6346 (at 1497nm) | 2.2151 (at 1440nm) |
| ne | 2.1486 (at 1550nm) | 2.710 (at 1530nm) | 1.4774 (at 1497nm) | 2.1413 (at 1440nm) | |
| Birefringence (ne-no) | 0.2039 (at 1550nm) | 0.256 (at 1530nm) | -0.1572 (at 1497nm) | -0.0738(at 1440nm) | |
| Mohs Hardness | 5 | 6.5 | 3 | 5 | |
| Deliquescence | None | None | Weak | None | |
| Transparency range | 0.4-5m m | 0.4-5m m | 0.35-2.3m m | 0.4-5m m | |
Advantages:
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Applications of YVO4 Crystals
Following drawings are the simple demonstrations of how the YVO4 crystals are used in Fiber Optic Isolator, Beam Displacers and Circulators.
1. Birefringent Wedges for Fiber-Optic Isolators
specifications
Aperture | 1.0 x 1.0 mm2 to 2 x 2 mm2 |
Dimension tolerance | +/-0.05mm |
Wedge Angle tolerance | +/-0.1 Deg. |
Optical axis orientation | +/-0.5 Deg. |
Flatness | l/4 @ 632.8 nm |
Surface Quality | 20-10 |
AR-coating | R<0.2% @1550nm+/-40nm |
Standard Size
P/N | Crystal | XL | Y | Z | q(deg.) | f(deg.) | AR@ |
YWE0101 | YVO4 | 0.5mm | 1..25mm | 1.25mm | 8 | 22.5 | 1550nm |
YWE0102 | YVO4 | 0.5mm | 1..25mm | 1.25mm | 5 | 22.5 | 1550nm |
Note: Other sizes and Coating are available upon request
2. YVO4 Beam Displacer
Optical Circulator
Interleaver
Specifications
Dimension tolerance:(+/- 0.05) x( +/- 0.05) x(+/- 0.1)mm |
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Optical axis orientation: +/-0.5deg. | |
Parallelism: <15 arc sec | |
Perpendicularity: <10 arc min | |
Flatness: l /4 @ 632.8 nm | |
Surface Quality: 20-10 | |
AR-coating: R<0.2% @ 1550 nm+/- 40 nm |
Note: Other sizes and specifications are available upon request
Standard Size
P/N | Crystal | Size | q(deg.) | f(deg.) | d | AR@ |
YBD0101 | YVO4 | 2x2x7mm | 45 | 0 | 0.70mm | 1550nm |
YBD0102 | YVO4 | 2.6x2.6x10mm | 45 | 0 | 1.00mm | 1550nm |
YBD0103 | YVO4 | 2.6x2.6x12mm | 45 | 0 | 1.20mm | 1550nm |
YBD0104 | YVO4 | 2.6x2.6x15mm | 45 | 0 | 1.50mm | 1550nm |