- 옵틱스 | Optics > Crystals > Laser Crystal
Product |
KTP Large nonlinear optical coefficient Wide angular bandwidth and small walk-off angle Broad temperature and spectral bandwidth High electro-optic coefficient and low dielectric constant Large figure of merit Nonhydroscopic, chemically and mechanically stable |
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Application |
SHG OPA OPG |
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Product Info
Chemical and Structural Properties of KTP Crystal
Crystal Structure | Orthorhombic, Space group Pna21, Point group mm2. |
Lattice Parameter | a=6.404 Å, b=10.616 Å, c=12.814 Å |
Melting Point | ~1172 °C |
Mohs Hardness | 5 |
Density | 3.01 g·cm-3 |
Thermal Conductivity | 13 W·m-1·K-1 |
Thermal Expansion Coefficient | αx=11×10-6/K, αy=9×10-6/K, αz=0.6×10-6/K |
Optical and Nonlinear Optical Properties of KTP Crystal
Transparency Range | 350 nm ~ 4500 nm |
Thermo-optic Coefficient [K-1](@1064nm) | dnx/dT=6.1×10-6 dny/dT=8.3×10-6 dnz/dT=14.5×10-6 |
Absorption Coefficient | <0.1% cm-1 @1064nm <1% cm-1 @532nm |
For Type II SHG of | Temperature Acceptance: 24 °C·cm-1 |
NLO Coefficients | deff(II)≈(d24-d15)sin2φsin2θ-(d15sin2φ + d24cos2φ)sinθ |
Non-vanished NLO Susceptibilities [pm/V] | d31=6.5 d24=7.6 d32=5 pm/V d15=6.1 d33=13.7 |
Sellmeier Equations | nx2=3.0065+0.03901/(λ2-0.04251)-0.01327λ2 |
Applications for SHG and SFG of Nd: lasers
KTP is the most commonly used material for frequency doubling of Nd:YAG and other Nd-doped lasers, particularly when the power density is at a low or medium level. To date, extra- and intra-cavity frequency doubled Nd:lasers using KTP have become a preferred pumping source for visible dye lasers and tunable Ti:Sapphire lasers as well as their amplifiers. They are also useful green sources for many research and industry applications.
* More than 80% conversion efficiency and 700mJ green laser were obtained with a 900mJ injection-seeded Q-switch Nd:YAG lasers by using extra-cavity KTP.
* 8W green laser was generated from a 15W LD pumped Nd:YVO4 with intra-cavity KTP.
* 200mW green outputs are generated from 1 W LD pumped Nd:YVO4 lasers by using THATSHIGH's 2x2x5mm KTP and 3x3x1mm Nd:YVO4.
* 2-5mw green outputs are generated from 180mw LD pumped Nd:YVO4 and KTP glued crystals. For more details, please refer to Glued Crystals.
KTP is also being used for intracavity mixing of 0.81μm diode and 1.064μm Nd:YAG laser to generate blue light and intracavity SHG of Nd:YAG or Nd:YAP lasers at 1.3μm to produce red light.
Applications for OPG, OPA and OPO
As an efficient OPO crystal pumped by a Nd:laser and its second harmonics, KTP plays an important role for parametric sources for tunable outputs from visible (600nm) to mid-IR (4500nm), as shown in Fig. 3 and Fig. 4.
Generally, KTP's OPOs provide stable and continuous pulse outputs (signal and idler) in fs, with 108 Hz repetition rate and a mW average power level. A KTP’s OPO that are pumped by a 1064nm Nd:YAG laser has generated as high as above 66% efficiency for degenerately converting to 2120nm.
The novel developed application is the non-critical phase-matched(NCPM) KTP OPO/OPA pumped by the X-cut KTP crystal. As shown in Fig.5, for pumping wavelength range from 0.7μm to 1 μm, the output can cover from 1.04μm to 1.45μm(signal) and from 2.15μm to 3.2μm(idler). More than 45% conversion efficiency was obtained with narrow output bandwidth and good beam quality.
THATSHIGH KTP Crystal Coating Service
□ Dual Band AR-coating (DBAR) for SHG of 1064nm with following features:
● Low reflectance (R<0.15% @ 1064nm; R<0.5% @ 532nm)
● High damage threshold (>400MW/cm2 @ 1064nm & 532nm)
● Long durability
□ Broad band coating for OPO applications.
□ High reflectivity coating: HR @ 1064nm (R>99.8%) & HT @ 532nm (T>95%)
□ Other coating types are available upon request.
THATSHIGH Specifications for KTP Crystal
Dimension Tolerance | (W±0.1mm) ×(H±0.1mm) ×(L+0.5/-0.1mm) (L≥2.5mm) |
Angle Tolerance | Δθ ≤ 0.25° Δφ ≤ 0.25° |
Clear Aperture | 90% of central area |
Chamfer | |
Chip | ≤ 0.1mm |
Damage Threshold | > 0.5 for 1064nm, TEM00, 10ns, 10Hz (AR-coated) |
Flatness | < λ/8 @ 633nm |
Parallelism | < 20" |
Perpendicularity | ≤ 5' |
Surface Quality [S/D] | < 10/5 |
Wavefront Distortion | < λ/8 @ 633nm |
Coating | AR coating available upon request |
Interior Quality | No visible scattering paths or centers [inspected by 50mW green laser] |