Details
Potassium titanyl phosphate (KTiOPO₄, KTP) is a widely used nonlinear optical crystal valued for its high optical quality, strong nonlinear response, and excellent mechanical stability. KTP features a broad transparency range from approximately 350 nm to 4.5 µm and a relatively high effective second-harmonic generation (SHG) coefficient, about three times higher than that of KDP. Its wide acceptance angle, small beam walk-off, high optical damage threshold, and availability of both Type I and Type II non-critical phase matching (NCPM) over a broad wavelength range make KTP highly versatile in nonlinear frequency conversion applications.
KTP is most commonly used for frequency doubling of Nd:YAG and other Nd-doped lasers, particularly in low to medium power density regimes, and is suitable for both intra-cavity and extra-cavity configurations. In addition to SHG, KTP can also be employed as a nonlinear medium in optical parametric oscillators (OPOs) for infrared generation up to approximately 4 µm, including use as a pump source for mid-IR OPO systems based on crystals such as ZGP.
A known limitation of standard KTP is its susceptibility to photochromic damage (grey-tracking), which can reduce nonlinear conversion efficiency under higher optical power. To address this, high grey-track resistance (HGTR) KTP crystals are available, significantly improving long-term stability and extending KTP performance toward higher-power applications.
Laserand also offers precision positioning mounts and housings for nonlinear crystals, enabling accurate alignment and stable integration into optical systems.
