Good UV Transmission KDP Crystal NLO Crystals For Q Switch
Potassium Dihydrogen Phosphate, known as KDP crystal (KH2PO4), and its isomorphic crystals, deuterated KDP, known as KD*P or DKDP crystal (KD2PO4), Ammonium Dihydrogen Phosphate, known as ADP crystal (NH4H2PO4) are widely used in frequency doubling, frequency tripling and frequency quadrupling of Nd-doped laser systems, as well as the electro-optical modulators. DKDP is mainly used in Pockels Cells, and ADP is also used in Acousto-Optical devices.
Characterized by good UV transmission, high damage threshold, and high birefringence, Potassium Dihydrogen Phosphate (KDP) and Potassium Dideuterium Phosphate (DKDP ) are among the most widely-used commercial NLO materials, though their NLO coefficients are relatively low. They are usually used for the doubling, tripling and quadrupling of Nd:YAG laser at room temperature. They are also excellent E-O crystals with high E-O coefficients, widely used as electro-optical modulators, such as Q-switches, Pockels Cells, etc.
Advantages:
Good UV transmission
High optical damage threshold
High birefringence
High nonlinear coefficients
Crystal | DKDP(KD*P) | KDP | ADP | |
Transmitting Range(nm): | 200~2150 | 180~1550 | 180~1500 | |
Absorption(%/cm): | 0.5 | 3 | - | |
Nonlinear Optical Coefficient (pm/V): | 0.40 | 0.43 | 0.52 | |
Damage Threshold: (GW/cm2 @1064nm) | 5 | 5 | 6 | |
Refractive Indices: | @1064nm | no=1.4931 | no=1.4942 | no=1.5071 |
ne=1.4583 | ne=1.4603 | ne=1.4685 | ||
@532nm | no=1.5074 | no=1.5129 | no=1.5280 | |
ne=1.4683 | ne=1.4709 | ne=1.4819 | ||
@355nm | no=1.5257 | no=1.5317 | no=1.5487 | |
ne=1.4833 | ne=1.4846 | ne=1.4994 | ||
@266nm | no=1.5539 | no=1.5599 | no=1.5797 | |
ne=1.5071 | ne=1.5105 | ne=1.5261 | ||
Sellmeier Equations: (l in µm) | N2 = A + B / (l2 - C) + Dl2/(l2- E) | |||
A | no | 2.2409 | 2.2576 | 2.3041 |
ne | 2.1260 | 2.1295 | 2.1643 | |
B | no | 0.0097 | 0.0101 | 0.0111 |
ne | 0.0086 | 0.0097 | 0.0097 | |
C | no | 0.0156 | 0.0142 | 0.0133 |
ne | 0.0120 | 0.0014 | 0.0129 | |
D | no | 2.2470 | 1.7623 | 15.1086 |
ne | 0.7844 | 0.7580 | 5.8057 | |
E | no | 126.9205 | 57.8984 | 400.0000 |
ne | 123.4032 | 127.0535 | 400.0000 |
Crystal | KD*P(DKDP) | KDP | ADP |
Crystal Structure: |
| ||
Density(g/cm3): | 2.355 | 2.332 | 1.799 |
Color: | Colorless | ||
Hygroscopic Susceptibility | High | ||
Thermal Conductivity(10-2W/cm·K): | k11=1.9;k33=2.1 | - | - |
Thermal Expansion Coefficients(10-5/K): | a11=1.9;a33=4.4 | - | - |