Q-Switched Crystals_Product Center_Chengdu Xinyuan Huibo Photoelectric Technology Co., Ltd

LiNbO3 is widely used as electro-optic modulators and Q-switches for Nd:YAG, Nd:YLF and Ti:Sapphire lasers as well as modulators for fiber optics. The following table list the specifications of a typical LiNbO3 crystal used as Q-switch with transverse E-O modulation. The light propagates in z-axis and electric field applies to x-axis. The electro-optic coefficients of LiNbO3 are: r33 = 32 pm/V, r31 = 10 pm/V, r22 = 6.8 pm/V at low frequency and r33 = 31 pm/V, r31= 8.6 pm/V, r22 = 3.4 pm/V at high electric frequency. The half–wave voltage: Vπ=λd/(2no3r22L), r c=(ne/no)3r33-r13.

Basic Properties
Crystal Structure	Single crystal,Synthetic
Density	4.64g/cm3
Melting Point	1253ºC
Transmission Range(50% of total transmission)	0.32-5.2um(thickness 6mm)
Molecular Weight	147.8456
Young’s Modulus	170GPa
Shear Modulus	68GPa
Bulk Modulus	112GPa
Dielectric Constant	82@298K
Cleavage Planes	No Cleavage
Poisson Ratio	0.25

LiNbO3 is also a good acousto-optic crystal and used for surface acoustic wave (SAW) wafer and A-O modulators. CASTECH provides acoustic (SAW) grade LiNbO3 crystals in wafers, as-cut boules, finished components and custom fabricated elements.

Typical SAW Properties
Cut Type	SAW VelocityVs (m/s)	Electromechanical Coupling Factork2s (%)	Temperature Coefficient of Velocity TCV (10-6/oC)	Temperature Coefficient of Delay TCD (10-6/oC)
127.86o Y-X	3970	5.5	-60	78
Y-X	3485	4.3	-85	95
Typical Specifications
Type Specifications	Boule		Wafer
Diameter	Φ3"	Φ4"	Φ3"	Φ4"
Length or Thickness(mm)	≤100	≤50	0.35-0.5
Orientation	127.86°Y, 64°Y, 135°Y, X, Y, Z, and other cut
Ref. Flat Orientation	X, Y
Ref. Flat Length	22±2mm	32±2mm	22±2mm	32±2mm
Front Side Polishing			Mirror polished 5-15 Å
Back Side Lapping			0.3-1.0 mm
Flatness (mm)			≤ 15
Bow (mm)			≤ 25

Technical Parameters
Size	9 X 9 X 25 mm3 or 4 X 4 X 15 mm3
Size	Other size is available upon request
Tolerance of size	Z-axis: ± 0.2 mm
Tolerance of size	X-axis and Y-axis:±0.1 mm
Chamfer	less than 0.5 mm at 45°
Accuracy of orientation	Z-axis: <± 5’
Accuracy of orientation	X-axis and Y-axis: < ± 10’
Parallelism	< 20"
Finish	10/5 scratch/dig
Flatness	λ/8 at 633 nm
AR-coating	R < 0.2% @ 1064 nm
Electrodes	Gold/Chrome plated on X-faces
Wavefront distortion	<λ/4 @ 633 nm
Extinction ratio	> 400:1 @ 633 nm, φ6 mm beam