KTP crystal is a popular crystal with excellent nonlinear optical properties. As a frequency conversion optical material, KTP crystal has been widely used in scientific research and many other fields, especially best for small and medium-sized power frequency doubling. Frequency doubler and photo-parametric amplifier produced by KTP crystal has been applied in solid-state tunable laser light sources.
KTP crystal, an optically positive twinning, with optical transparency range 350nm～4.5um, can realize the phase match of frequency doubling, sum frequency and optical parametric oscillation for 1.064um Ion neodymium laser and other wavelength laser (usually with type II phase match).
The nonlinear coefficient is 1.4 pm/V, 2.65 pm/V and 10.7 pm/V respectively for d31, d32 and d33. The nonlinear coefficient of d31 is more than 20 times higher than that of KDP’s d36. KTP crystal, with high light damage threshold, can be used in medium-power laser frequency doubling. KTP crystals have good mechanical properties and physico-chemical property, and are insoluble in water and organic solvents, non deliquescent with melting point 1150℃. Parts of KTP crystal will decompose while melting. KTP crystal also have large temperature and angle tolerance.
KTP crystals have very important nonlinear characteristics as follows:
- Large nonlinear optical coefficient(about 15 times large than that of KDP)
- Wide receiving angle and small walk-off angle
- Wide transmittance
- High photoelectric conversion efficiency and low dielectric constant
- Good physics, chemistry and mechanical property
- High heat transfer coefficient (two times high than BBN crystal)
- Low mismatch
- Cost-effective compared with BBO and LBO