Refractive index database

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Optical constants of KTiOPO4 (Potassium titanyl phosphate, KTP)
Kato and Takaoka 2002: n(β) 0.43–3.54 µm

Wavelength: µm

Complex refractive index (n+ik)[ i ]

n   k   LogX   LogY   eV

Derived optical constants

Dispersion formula [ i ]



nβ; 20 °C.


K. Kato and E. Takaoka. Sellmeier and thermo-optic dispersion formulas for KTP, Appl. Opt. 41, 5040-5044 (2002).


[Expressions for n]   [CSV - comma separated]   [TXT - tab separated]   [Full database record]


Potassium titanyl phosphate, KTiOPO4 (KTP)

Potassium titanyl phosphate (KTiOPO4, commonly abbreviated as KTP) is a nonlinear optical material widely used in a variety of photonic applications, including frequency doubling of laser sources, optical parametric oscillation, and electro-optic modulation. KTP exhibits a broad transparency range from approximately 350 nm to 4.5 μm. One of its noteworthy advantages is its high damage threshold, which makes it suitable for high-power laser applications. The crystal also exhibits good phase-matching conditions over an extensive range of wavelengths, making it a material of choice for tunable and multi-wavelength laser sources. It's commonly utilized in green laser pointers via frequency doubling of Nd:YAG or Nd:YVO4 lasers, which emit at 1064 nm. Overall, KTP's combination of optical and mechanical properties make it an important material in the field of nonlinear optics.

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