KTP crystal is a kind of popular nonlinear optical crystal with excellent nonlinear optical properties. As a frequency conversion optical material, KTP crystal had been widely used in scientific research and technique and many other fields, especial best for small and medium-sized power frequency doubling. Frequency doubler and photoparametric amplifier produced by KTP crystal had been had been applied in solid-state tunable laser light source.
KTP crystal, a 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 Ⅱtype phase match）.
The nonlinear coefficient is 1.4 pm/V 2.65pm/V and 10.7pm/V respectively for d31、d32、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 physicochemical 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
High photoelectric conversion efficiency and low dielectric constant
Good physics, chemistry and mechanical property
High heat transfer coefficient (two times high than BBN crystal)
Cost-effective compared with BBO and LBO