Potassium Titanyle Phosphate

Material
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!

Properties
Optical properties
Transmission range
350 ‐ 4500
Refractive index @532 nm
nx = 1,779

ny = 1,789

nz = 1,889

Refractive index @ 1064 nm
nx = 1,738

ny = 1,746

nz = 1,830

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
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
Chemical formula
KTiOPO4
Density in g/cm3
3,01
Melting point in °C
1172
Lattice constants in Å
a= 12,814

b = 6,404

c = 10,616

Crystal structure
orthorhombic
Curie-point in °C
936
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
Mohs hardness
∼5
Dielectric constant
εeff = 13
Spezific heat capacity in cal/(g · °C)
0,1643
Spectral properties
sample thickness: 10 mm