KTP Nonlinear crystal Potassium Titanyl Phosphate
KTP crystals is the most commonly used material for frequency doubling of Nd-doped lasers, particularly at the low or medium power density.It is widely used for frequency mixing to generate Red/Green/Blue output, and for OPO and OPA to generate visible to mid-infrared tunable output. It is also used for many E-O devices such as Q-switches and E-O modulators.
Potassium Titanyl Phosphate (KTiOPO4 or KTP) is widely used in both commercial and military lasers including laboratory and medical systems, range-finders, lidar, optical communication and industrial systems.
Main applications:
- Frequency Doubling (SHG) of Nd-doped Lasers for Green/Red Output;
- Frequency Mixing (SFM) of Nd Laser and Diode Laser for Blue Output;
- Parametric Sources (OPG, OPA and OPO) for 600nm – 4500nm Tunable Ouptut;
- E-O Modulators, Optical Switches, Directional Couplers;
- Optical Waveguides for Integrated NLO and E-O DevicesOPA andOPO.
Advantages:
- Large nonlinear optical coefficient;
- Wide angular bandwidth and small walk-off angle
- Broad temperature and spectral bandwidth;
- High Electro-Optics(E-O)coefficient and low dielectric constant;
- Non-hygroscopic, chemically and mechanically stable
Optical and Nonlinear properties of KTP crystal
| Transparency Range | 350~4500nm |
| SHG Phase Matchable Range | 497 ~ 1800nm (Type II) |
| Therm-optic Coefficient (/℃, λ in μm) | dnx/dT=1.1X10-5 dny/dT=1.3X10-5 dnz/dT=1.6X10-5 |
| Absorption Coefficients | <0.1%/cm at 1064nm <1%/cm at 532nm |
| Angle Acceptance | 14.2mrad·cm (φ);55.3mrad·cm (θ) for Type II SHG of a Nd:YAG laser at 1064nm |
| Temperature Acceptance | 24°C·cm for Type II SHG of a Nd:YAG laser at 1064nm |
| Spectral Acceptance | 0.56nm·cm for Type II SHG of a Nd:YAG laser at 1064nm |
| Walk-off Angle | 0.55° for Type II SHG of a Nd:YAG laser at 1064nm |
| NLO Coefficients | deff(II)≈(d24 – d15)sin2Φsin2θ – (d15sin2Φ + d24cos2Φ)sinθ |
| Non-vanished NLO susceptibilities | d31=6.5 pm/V d24=7.6 pm/V d32= 5 pm/V d15=6.1 pm/V d33=13.7 pm/V |
| Sellmeier Equations (λ in μm) | nx2=3.0065+0.03901/(λ2-0.04251)-0.01327λ2 ny2=3.0333+0.04154/(λ2-0.04547)-0.01408λ2 nz2=3.3134+0.05694/(λ2-0.05658)-0.01682λ2 |
| Electro-optic Coefficients:
r13 r23 r33 r51 r42 |
Low and High frequency (pm/V)
9.5 and 8.8 15.7and 13.8 36.3 and 35 7.3 and 6.9 9.3 and 8.8 |
| Relative Dielectric Constant | εeff=13 |
Physical properties of KTP crystal
| Crystal Structure | Orthorhombic, space group Pna21,point group mm2 |
| Lattice Parameter | a=6.404Å, b=10.616Å, c=12.814A, Z=8 |
| Melting Point | About 1172°C |
| Mohs Hardness | 5 |
| Density | 3.01 g/cm3 |
| Refractive indices | nX = 1,7404; nY = 1,7479; nZ = 1,8296 @1064 nm |
| Thermal Conductivity | 13W/m/K |
| Thermal Expansion Coefficients | ax=11×10-6/℃, ay=9×10-6/℃, az=0.6×10-6/℃ |
HGO offers KTP specifications:
| Tolerance of cutting angle | △θ≤±0.25°,△φ≤±0.25° |
| Tolerance of dimension | Dimension+0/-0.1 mm，L：±0.1mm |
| Flatness | λ/10 @ 632.8nm |
| Wavefront distortion | λ/8@ 632.8nm |
| Surface quality | 10/5 per MIL-O-13830A |
| Parallelism | 20″ |
| Perpendicularity | 5′ |
| Clear Aperture: | > 90% |
| Chamfer: | < 0.1 mm @ 45° |
| Size | Upon customer request |
| Coating | AR/HR coating upon customer’s request |
| Damage Threshold | 750MW/CM2 at 1064nm, TEM00, 10ns, 10Hz |
| Quality Warranty Period | One year under proper use |
