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KTA Crystal (KTiOPO4)

Crystals >>> Nonlinear Crystals >>>  KTA Crystal

Potassium Titanyle Arsenate(KTiOAsO4), or KTA crystal,  is an excellent nonlinear optical crystal for Optical Parametric Oscillation (OPO) Application.  OPO devices based on KTAs are reliable, solid state sources of tunable laser radiation exhibiting energy conversion efficiencies above 50%.  In addition KTA has a very high damage threshold.  

In comparison to KTP, KTA crystals feature large non-linear optical and electro-optical coefficients and have significantly reduced absorption in the 2.0 - 5.0 mm range.  Its low dielectric constants, low loss tangent and ionic conductivities are orders of magnitude less than that of KTP.


  • Large nonlinear optical and electro-optical coefficients

  • Wide angular bandwidth and small walk-off angle

  • Broad temperature and spectral bandwidth

  • Low dielectric constants, loss tangent and ionic conductivities (much less than that of KTP)

  • High damage threshold


  • Frequency Doubling (Second Harmonic Generation SHG)

  • Sum and Difference Frequency Generation (SFG)/(DFG) 

  • Optical Parametric Oscillation (OPO)

  • Electro-Optical Q-switch and modulation for Optical waveguides

Main Specifications
Diameter Tolerance


Parallelism better than 30 arc second
Perpendicularity better than 30 arc min
Surface Quality




Roughness <10 Rms

q < 0.5, f < 0.5

Clear Aperture

> 90% central area

Transmitted Wavefront Distortion

Less than l/8@633nm


AR Coating Available


Physical and Chemical Properties
Formulation  KTiOAsO4 
Crystal structure Orthorhombic 
Lattice parameters a=13.125     b=6.5716     c=10.786
Point group mm2
Hardness (Mohs)  near 5
Hygroscopic susceptibility none 
Chemically  stable 
Density  3.454 g/cm
Thermal conductivity


K2 K3




Ionic conductivity (room temperature, 10kHz) 0.7 - 3.4.10-6 S/cm 
Optical and NLO Properties
Transparency range 0.35 - 5.3 m
Average refractive index 1.8
Absorption @ 1064 nm <0.05 %/cm 
@ 1533 nm <0.05 %/cm 
@ 3475 nm <5%/cm 
NCPM Angle
q j
Pump  Signal  Idler 
1064 nm 1533 nm 3475 nm 
Electro-optical constants
(low frequency)
r33 r23 r13
37.5 pm/V 15.4 pm/V 11.5 pm/V 



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