KTP crystal (KTiOPO4 or Potassium titanyl phosphate) is a nonlinear optical material commonly appilication for frequency doubling of Nd:YAG lasers and other Nd-doped lasers, particularly at a low or medium-power density.
KTP crystal exhibits a high optical quality, broad transparency range, wide acceptance angle, small walk-off, and type I and II non-critical phase-matching (NCPM) in a wide wavelength range. KTP crystal has a relatively high effective SHG coefficient (about 3 times higher than that for KDP) and fairly high damage threshold (>500 MW/cm²).
KTP nonlinear crystals can be used as a nonlinear OPO medium for IR generation up to 4 µm and used as a pump source for mid-IR nonlinear crystal-based optical parametric oscillators, such as ZGP OPO
| Thickness | 3 mm ~ 150 mm or Upon customer request |
| Thickness/Diameter Tolerance | ±0.05 mm |
| Orientation Tolerence | < 0.5° |
| Surface Quality | 10/5 S/D per MIL-O-13830A |
| Parallelism | < 10 arcsec |
| Perpendicularity | < 5 arcmin |
| Clear Aperture | > 90% |
| Wavefront Distortion | λ/8 @ 633 nm |
| Surface Flatness | < λ/8 @ 632.8 nm |
| Chamfer | < 0.1 mm @ 45° |
| Coating | AR/HR/PR coating upon customer's request |
| Chemical Formula | KTiOPO4 |
|---|---|
| Crystal Structure | Orthorhombic, space group Pna21,point group mm2 |
| Lattice Constant | a=6.404Å, b=10.616Å, c=12.814A, Z=8 |
| Density | 3.01 g/cm3 |
| Melting Point | About 1172°C |
| Refractive indices | nX = 1,7404 nY = 1,7479 nZ = 1,8296 @1064 nm |
| Hardness (Mohs) | 5 |
| Thermal Conductivity | 13W/m/K |
| Thermal Expansion Coefficients | ax=11x10-6/℃ ay=9x10-6/℃ az=0.6x10-6/℃ |
| Transparency Range | 350 nm ~ 4500 nm |
| SHG Phase Matchable Range | 497 ~ 1800 nm (Type II) |
| Therm-optic Coefficient (/℃, λ in μm) | dnx/dT=1.1*10-5 dny/dT=1.3*10-5 dnz/dT=1.6*10-5 |
| Absorption Coefficients | < 0.1%/cm at 1064 nm < 1%/cm at 532 nm |
| Angle Acceptance | 14.2 mrad·cm (φ); 55.3 mrad·cm (θ) for Type II SHG of a Nd:YAG laser at 1064 nm |
| Temperature Acceptance | 24°C·cm for Type II SHG of a Nd:YAG laser at 1064 nm |
| Spectral Acceptance | 0.56 nm·cm for Type II SHG of a Nd:YAG laser at 1064 nm |
| Walk-off Angle | 0.55° for Type II SHG of a Nd:YAG laser at 1064 nm |
| NLO Coefficients | deff(II)≈(d24 - d15)sin2Φsin2θ - (d15sin2Φ + d24cos2Φ)sinθ |
| Relative Dielectric Constant | εeff=13 |
Stock specification list
| Part Number | Size | Theta, θ | Phi, φ | Coating S1/S2 | Application |
|---|---|---|---|---|---|
| KTP-Cry-001 | 3x3x5 mm | 90 | 23.5 | AR/AR@1064+532 nm | SHG@1064 nm |
| KTP-Cry-002 | 3x3x10 mm | 90 | 23.5 | AR/AR@1064+532 nm | SHG@1064 nm |
| KTP-Cry-003 | 7x7x9 mm | 90 | 23.5 | AR/AR@1064+532 nm | SHG@1064 nm |
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