KTP (Potassium Titanyl Phosphate, KTiOPO4) is a nonlinear optical material generally used for doubling of solid-state lasers, such as Nd:YAG. The crystal has a relatively high optical damage threshold, a large optical nonlinearity of second-harmonic generation (SHG) and excellent thermal stability. Its SHG coefficient is approximately three times higher than KDP, and it is often used as an optical parametric oscillator (OPO) for near IR generation up to 3 µm.

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
High thermal conductivity
Moisture free
Minimum mismatch gradient
Low cost compare with BBO and LBO