Crystal Structure

Orthorhombic, space group Pna2₁, point group mm

Cell parameters

a = 6.404 Å
b = 10.616 Å
c = 12.814 Å
Z = 8

Melting Point

1172 °C incongruent

Curie Point

936 °C

Mohs hardness

≈ 5

Density

3.01 g / cm³

Color

Colorless

Hygroscopic susceptibility

No

Specific heat

0.1643 cal / g• °C

Thermal conductivity

0.13 W / cm / °K

Electrical conductivity

3.5 x 10^-8 s/cm (c-axis, 22°C, 1 KHz)

Phase matchable SHG range

497 – 1800 nm

Nonlinear optical coefficients

d₃₁ = 6.5 pm / v
d₃₂ = 5 pm / v
d₃₃ = 13.7 pm / v
d₂₄ = 7.6 pm / v
d₁₅ = 6.1 pm / v
d_eff(І?І?) ≈(d₂₄ – d₁₅) sin2fsin2q - (d₁₅sin²f + d₂₄cos²f) sinq

For type II SHG of a Nd: YAG

Laser at 1064 nm

Pm angle: q = 90°C, f = 23.3°
Effective SHG coefficient: d_eff» 8.3 xd₃₆ (KDP)
Angular acceptance: 20 mrad-cm
Temperature acceptance: 25 °C-cm

Spectral acceptance: 5.6 Å –cm
Walk-off angle: 4.5 mrad (0.26°)
Optical damage threshold: > 450 MW / cm², 
(@ 1064 nm, 10 ns, 10 Hz)

R₁₃

9.5

8.8

R₂₃

15.7

13.8

R₃₃

36.3

35.0

R₅₁

7.3

6.9

R₄₂

9.3

8.8

Dielectric constant

E_eff= 13

Transmitting range:Density

350 – 4500 nm

Refractive indices
1064 nm
532 nm

n_x
1.7377
1.7780

n_y
1.7453
1.7886

n_z
1.8297
1.8887

Sellmeier equations

n_x² = 3.0065 + 0.03901 / (l² - 0.04251) – 0.01327 l²
n_y² = 3.0333 + 0.04154 / (l² – 0.04547) – 0.01408 l²
n_z² = 3.0065 + 0.05694 / (l² – 0.05658) – 0.01682 l²

Therm – optic coefficients

dn_x / dT = 1.1 x 10^-5 / °C
dn_y / dT = 1.3 x 10^-5 / °C
dn_z / dT = 1.6 x 10^-5 / °C

Absorption coefficient

αa < 1% cm^-1 @ 1064 nm and 532 nm