Potassium Titanyle Phosphate
KTP
Potassium Titanyle Phosphate (KTP, or KTiOPO4) is an excellent non-linear crystal known for its high NLO coefficient. It exhibits high optical quality, broad transparent range, relatively high effective SHG coefficient (about 3 times higher than KDP), very high optical damage threshold, wide acceptance angle, small walk-off and type I and type II non-critical phase-matching (NCPM) in a wide wavelength range. It is being used for frequency doubling of Nd:YAG lasers and other Nd-doped lasers, particularly at the low or medium power density.
The most popular application is for Second Harmonic Generation (SHG) and Optical Parametric Oscillators (OPO). Temperature-noncritical phase matching is available for many Nd-doped active elements!
Optical and spectral properties | |
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Transmission range | 350 ‐ 4500
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Refractive index @532 nm | nx = 1,779 ny = 1,789 nz = 1,889
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Refractive index @ 1064 nm | nx = 1,738 ny = 1,746 nz = 1,830
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Average refractive index | 1,8 |
NLO coefficients in pm/V, @532 nm to 1064 nm | d31 = 6,5 d32 = 5,0 d33 = 13,7 d34 = 6,1 |
Absorption loss in %/cm @532 nm and @1064 nm | <0,001
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For type ΙΙ SHG of a Nd:YAG laser at 1064 nm: | |
Temperature acceptance in °C·cm | 24 |
Spectral acceptance in nm·cm | 0,56 |
Angular acceptance in mrad·cm | φ = 14,2 θ = 55,3 |
Walk-off-angle | 0,55° |
Physical properties | |
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Chemical formula | KTiOPO4 |
Density in g/cm3 | 3,01
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Melting point in °C | 1172
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Lattice constants in Å | a= 12,814 b = 6,404 c = 10,616 |
Crystal structure | orthorhombic
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Curie-point in °C | 936
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Thermal conductivity in W/(m·K) | 13 |
Thermal expansion in 1/°C | 8,7 ·10-6 10,5 ·10-6 -0,2 ·10-6 |
Electrical conductivity in S/cm (c-axsis, 22oC, 1kHz) | 3,5 ·10-8
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Mohs hardness | ∼5
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Dielectric constant | εeff = 13 |
Spezific heat capacity in cal/(g · °C) | 0,1643
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Spectral properties | |
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sample thickness: 10 mm |