Potassium Titanyl Phosphate (KTP)

KOMLAS offers high quality KTP-, BBO- and LBO- crystals. The right material should be chosen taking into consideration the criteria transmission, damage threshold, efficiency of the nonlinear effect, phase matching range and laser beam quality.

The damage threshold is a function of the wavelength of fundamental and harmonic radiation, pulse duration, beam profile and other parameters. For guidance typical values are given in the table ( = 1064 nm, pulse duration 1.3 ns). max. energy density [J/cm²]: KTP 4.6 BBO 9.9 LBO 18.9

KTP (KTiOPO₄) is a nonlinear optical crystal, which combines superior properties such as large nonlinear optical coefficients, wide angular bandwidth and small walk-off angle, broad temperature and spectral bandwidth, high electro-optic coefficient and low dielectric constant and a large figure of merit for optical waveguide modulators. It is nonhygroscopic and has good chemical and mechanical properties.

The very high effective nonlinearity and the phase matching range (0.99 - 3.3 µm) allows KTP to be used as intracavity and extracavity frequency doublers for the most commonly used lasers. Today KTP is the most commonly used material for frequency doubling of Nd.YAG lasers (green lasers).

As a active material for OPG, OPA or OPO, KTP can most usefully be pumped by Nd lasers and their second harmonic or any other source with intermediate wavelength, such as a dye laser (near 600 nm). Other applications are frequency mixing (SFM) of Nd:YAG laser and diode laser for blue output, electro-optic modulators, optical switches and optical waveguides for integrated nonlinear optical and electro-optic devices.

Crystal structure Point group Space group Lattice constants [Å] Density [g/cm-3] Melting point [°C] Transitition temperature [°C] Mohs hardness Absorption [cm-1] at 1064 nm 532 nm Thermal expansion coefficients [10–6/K]  Refractive indices at 1064 nm 532 nm Thermo-optic coefficients [10-5/K]

orthorhombic mm² Pna21 a= 12.814, b= 6.404, c= 10.616 3.01   1170 936 5 < 0.001   < 0.001 α1 = 11.0, α2 = 8.9, α3 = 0.6 nx = 1.7385, ny = 1.7458, nz = 1.8299 nx = 1.7782, ny = 1.7893, nz = 1.1885 dnx/dT = 1.1, dny/dT = 1.3, dnz/dT = 1.6

Wavelength dispersion of refractive index (Sellmeier equitions)
n_x²= 3.0065 +0.03901/(λ² -0.04251) - 0.01327 λ² (λ in µm, T=20 °C)
n_y²= 3.0333 +0.04154/(λ² -0.04547) - 0.01408 λ² (λ in µm, T=20 °C)
n_z²= 3.3134 +0.05694/(λ² -0.05658) - 0.01682 λ² (λ in µm, T=20 °C)

Walk-off for Type 2 SHG @ 1064 nm [mrad] 3

Effective nonlinearity d31[m/V] d32[m/V] d33[m/V] d24[m/V] d15[m/V]

3.5 x 10-12  4.6 x 10-12  15.5 x 10-12  5.0 x 10-12  2.5 x 10-12

KOMLAS offers:

• Crystal length up to 20 mm and aperture up to 20 mm x 20 mm
• Dualband and tripleband AR coatings
• Determination of necessary angular orientation