Potassium Niobate
KNbO3
Potassium Niobate

Crystal properties

Symmetry

Orthorhombic

Point group

2 mm (@ temperature fromm –50°C to 222 ± 4°C)

Lattice Parameters

A = 5.68961 Å
B = 3.9692 Å
C = 5.7256 Å
 

Thermal Expansion.

A= 5.010 x 10-6/°C
Ab = 1.410 x 10-5/°C
Ac = 5.010 x 10-7/°C

Density

4.62 g/cm³

Hardness (Mohs)

5

Phase Transition Temperature

-50 °C; 220°C; 430°C

Transsparent Range

400 – 4500 nm

Absorption loss

£ 1 %/cm @ 1064 nm

Damage threshold

³ 4 J/cm² @ 527 nm (500 ps, single pulse)
³ 6 J/cm² @1054 nm (700 ps, single pulse)

Principal Axes Û Crystallographic Axes

x Û c, y Û a, z Û b
( ie. Nb> na> n)

Typical Refractive Index

na (ny)

n(nz)

nc (nx)

430 nm

2.4145

2.4974

2.2771

532 nm

2.3223

2.3813

2.2022

860 nm

2.2372

2.2784

2.1338

1064

2.2195

2.2576

2.1194

Sellmeier Equations: ( l in mm)

nx2 = 4.4208 + 0.10044 /(l2 – 0.054084) – 0.019592 l2

ny2 = 4.8355 + 0.12839 /(l2 – 0.056342) – 0.025379 l2

nx2 = 4.9873 + 0.15149 /(l2 – 0.064143) – 0.028775 l2