KTP — Frequency Doubling Of Nd:yag Lasers And Other Nd-doped Lasers
Product Description
KTP is the most commonly used material for frequency doubling of Nd:YAG lasers and other Nd-doped lasers, particularly at the low or medium power density.
Advantages
● Efficient frequency conversion(1064nm SHG conversion efficiency is about 80%)
● Large nonlinear optical coefficients(15 times that of KDP)
● Wide angular bandwidth and small walk-off angle
● Broad temperature and spectral bandwidth
● High thermal conductivity (2 times that of BNN crystal )
● Moisture free
● Minimum mismatch gradient
● Super-polished optical surface
● No decomposition below 900°C
● Mechanically stable
● Low cost compare with BBO and LBO
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 0.6mm-4.5mm Tunable Output
● Electrical Optical(E-O) Modulators, Optical Switches, and Directional Couplers
● Optical Waveguides for Integrated NLO and E-O Devices
Frequency Conversion
KTP was first introduced as the NLO crystal for Nd doped laser systems with high conversion efficiency. Under certain conditions, the conversion efficiency was reported to 80%, which leaves other NLO crystals far behind.
Recently, with the development of laser diodes, KTP is widely used as SHG devices in diode pumped Nd:YVO4 solid laser systems to output green laser, and also to make the laser system very compact.
KTP For OPA, OPO Applications
In addition to its wide use as a frequency doubling device in Nd-doped laser systems for Green/Red output, KTP is also one of the most important crystals in parametric sources for tunable output from visible (600nm) to mid-IR (4500nm) due to the popularity of its pumped sources, the fundamental and second harmonic of a Nd:YAG or Nd:YLF lasers.
One of the most useful applications is the non-critical phase-matched (NCPM) KTP OPO/OPA pumped by the tunable lasers to obtain a high conversion efficiency.KTP OPO results in stable continuous outputs of femto-second pulse of 108 Hz repetition rate and milli-watt average power levels in both signal and idler outputs.
Pumped by Nd-doped lasers, KTP OPO has obtained above 66% conversion efficiency for down-conversion from 1060nm to 2120nm.
Electro-Optical Modulators
KTP crystal can be used as electro-optical modulators. For more information, please contact our sales engineers.
Basic Properties
| Crystal structure | Orthorhombic |
| Melting point | 1172°C |
| Curie Point | 936°C |
| Lattice parameters | a=6.404Å, b=10.615Å, c=12.814Å, Z=8 |
| Temperature of decomposition | ~1150°C |
| Transition temperature | 936°C |
| Mohs hardness | »5 |
| Density | 2.945 g/cm3 |
| Color | colorless |
| Hygroscopic Susceptibility | No |
| Specific heat | 0.1737 cal/g.°C |
| Thermal conductivity | 0.13 W/cm/°C |
| Electrical conductivity | 3.5x10-8 s/cm (c-axis, 22°C, 1KHz) |
| Thermal expansion coefficients | a1 = 11 x 10-6 °C-1 |
| a2 = 9 x 10-6 °C-1 | |
| a3 = 0.6 x 10-6 °C-1 | |
| Thermal conductivity coefficients | k1 = 2.0 x 10-2 W/cm °C |
| k2 = 3.0 x 10-2 W/cm °C | |
| k3 = 3.3 x 10-2 W/cm °C | |
| Transmitting range | 350nm ~ 4500nm |
| Phase Matching Range | 984nm ~ 3400nm |
| Absorption coefficients | a < 1%/cm @1064nm and 532nm |
| Nonlinear Properties | |
| Phase matching range | 497nm – 3300 nm |
| Nonlinear coefficients (@ 10-64nm) |
d31=2.54pm/V, d31=4.35pm/V, d31=16.9pm/V d24=3.64pm/V, d15=1.91pm/V at 1.064 mm |
| Effective nonlinear optical coefficients | deff(II)≈ (d24 - d15)sin2qsin2j - (d15sin2j + d24cos2j)sinq |
Type II SHG of 1064nm Laser
| Phase matching angle | q=90°, f=23.2° |
| Effective nonlinear optical coefficients | deff » 8.3 x d36(KDP) |
| Angular acceptance | Dθ= 75 mrad Dφ= 18 mrad |
| Temperature acceptance | 25°C.cm |
| Spectral acceptance | 5.6 Åcm |
| Walk-off angle | 1 mrad |
| Optical damage threshold | 1.5-2.0MW/cm2 |
Technical Parameters
| Dimension | 1x1x0.05 - 30x30x40 mm |
| Phase matching type | Type II, θ=90°; φ=phase-matching angle |
| Typical Coating | S1&S2: AR @1064nm R<0.1%; AR @ 532nm, R<0.25%. b) S1: HR @1064nm, R>99.8%; HT @808nm, T>5% S2: AR @1064nm, R<0.1%; AR @532nm, R<0.25% Customized coating available upon customer request. |
| Angle tolerance | 6' Δθ< ± 0.5°; Δφ< ±0.5° |
| Dimension tolerance | ±0.02 - 0.1 mm (W ± 0.1mm) x (H ± 0.1mm) x (L + 0.2mm/-0.1mm) for NKC series |
| Flatness | λ/8 @ 633nm |
| Scratch/Dig code | 10/5 Scratch/dig per MIL-O-13830A |
| Parallelism | <10' better than 10 arc seconds for NKC series |
| Perpendicularity | 5' 5 arc minutes for NKC series |
| Wavefront distortion | less than λ/8 @ 633nm |
| Clear aperture | 90% central area |
| Working temperature | 25°C - 80°C |
| Homogeneity | dn ~10-6/cm |
