Sinoceramics | Optical Components

KDP and KD*P

Potassium Dihydrogen Phosphate (KDP) and Potassium Dideuterium Phosphate (KD*P) are among the most widely-used commercial NLO materials. They are commonly used for doubling, tripling and quadrupling of Nd:YAG laser at the room temperature. In addition, they are also excellent electro-optic crystals with high electro-optic coefficients, widely used as electro-optical modulators, Q-switches, and Pockels Cells, etc.

Good UV transmission
High optical damage threshold
High birefringence high nonlinear coefficients

Physical and Optical Properties

.	KDP		*KDP**
Chemical Formula	KH₂PO₄		KD₂PO₄
Crystal Structure	Tetragonal		Teragonal
Transmission Range	200-1500nm		200-1600nm
Nonlinear Coefficients	d₃₆ = 0.44pm/v		d₃₆ = 0.04pm/v
Refractive Indicies (@ 1064nm)	n_o = 1.4938	n_e = 1.4599	n_o = 1.4938	n_e = 1.4599
Electro-Optical Coefficients	r₄₁ = 8.8pm/v	r₆₃ = 10.3pm/v	r₄₃ = 8.8pm/v	r₆₃ = 25pm/v
Longitudinal Half-Wave Voltage	V_p = 7.56KV (1 = 546nm)		V_p = 2.98KV (1 = 546nm)
Absorption	0.07/cm		0.006/cm
Temperature Synchronism Width	11.5°C·cm		7.4°C·cm
Spectral Synchronism Width	106°·cm		32°·cm
Angle Synchronism Width	0.84mrad·cm		0.94mrad·cm
Absorption Coefficient , cm^-1	0.07		0.006
Mohs Hardness	2.5		2.5
Optical Damage Threshold	> 5GW/cm²		> 3GW/cm²
Extinction Ratio	.		30dB

Sellmeir Equations for KDP:
n_o² = 2.259276 + 0.01008956 / (λ² - 0.012942625) + 13.005522λ² / (λ² - 400)
n_e² = 2.132668 + 0.008637494 / (λ² - 0.012281043) + 3.2279924λ² / (λ² - 400)

Sellmeir Equations for KD*P:
n_o² = 1.9575544 + 0.2901391 / (λ² - 0.0281399) - 0.02824391λ² + 0.004977826λ⁴
n_e² = 1.5005779 + 0.6276034 / (λ² - 0.0131558) - 0.01054063λ² + 0.002243821λ⁴

Application:

Second, third, and fourth harmonic generation of Nd:lasers
Frequency doubling of dyer laser
High power laser frequency conversion materials
Shutter for high speed photography
Electro-optical modulator and Q switches

*KDP Single Crystal Standards**
Designation	Operation	Input	Output
53.7°	SHG (II)	1064nm	532nm
59.5°	THG (II)	1064nm + 532nm	355nm
63.7°	SFM (II)	1064nm + (421-1000nm)	302 - 515nm
86°	FHG (I) angle tune	532nm	266nm
90°	FHG (I) temperature tune	532nm	266nm
36.6°	SHG (I)	1064nm	362nm
46.8°	THG (I)	1064nm + 352nm	355nm

KDP and KD*P Specifications

Wavefront Distortion:	< 8 @ 633nm
Dimension Tolerance:	(W ± 0.1mm)x(H ± 0.1mm)x(L +0.2mm/ -0.1mm)
Clear Aperture:	> 90% central area
Flatness:	λ /8 @633nm
Surface Quality:	10/5 to MIL-O-13830A
Parallelism:	Better than 20 arc seconds
Perpendicularity:	5 arc minutes
Angle Tolerance:	Δθ < 0.3° , Δφ < 0.3°
Quality Warranty Period:	One year under proper use