LiNbO₃

概述

LiNbO3 is widely used in electro-optical equipment such as photomodulated Q-switches due to its very large electro-optical coefficient, acousto-optic coefficient and high damage threshold. The electro-optical modulation of lithium niobate is transverse modulation, in which the light propagates along the Z-axis direction, and the electrode is plated on the X side to generate an electric field in the X direction.

General parameters

Form Tolerance(mm)	±0.1	Length tolerance(mm)	±0.1
Optical axis angle tolerance	±0.5°	Effective aperture	＞90%
Face	＜λ/8@633nm	Through wavefront distortion	＜λ/4@633nm
Eccentricity	＜20〞	Side verticality	＜5ˊ
Finish	20/10	Damage threshold	＞5J/cm²,20ns,20Hz,1064nm
Tangential	z切	Design wavelength(nm)	1064
End face coating	Both end faces are coated with anti-reflection film, and the residual reflectivity on one side is residual R＜0.25%@1064nm	Side coating	X-side gold-plated electrode

Peculiarity

Crystal structure: Lithium niobate belongs to the trigonal crystal system and has various properties such as ferroelectric, piezoelectric, optoelectric, and nonlinear optics.
Optical properties: Good light transmittance in the 0.4-5μm band, the refractive index ellipsoid is a rotating ellipsoid with Z as the symmetry axis, and the cross-section perpendicular to the Z axis is a circle.
Electro-optical effect: The electro-optical coefficient is large, and it is often used for electro-optical modulation.

Physical and optical properties

Crystal structure	Trigonal, space group R3c
Lattice parameters	a=0.515Å, c=13.863Å, Z=6Å
Melting point	1255±5℃
Curie Point	1140±5℃
Mohs hardness	5
Density	4.64g/cm³
Absorption coefficient	~0.1%/cm@1064nm
Water solubility	Insoluble in water
Relative dielectric constant	e^T₁₁/e₀: 85; e^T₃₃/e₀: 29.5
Coefficient of thermal expansion( @ 25℃)	\|\|a, 2.0x10^-6/K; \|\|c, 2.2x10^-6/K
Thermal conductivity	38 W /m /K @ 25℃
Light transmission range	420-5200nm
Optical uniformity	~5x10^-5/cm
Sellmeier equation( λ in um)	n_o²=4.9048+0.11768/(λ²-0.04750)-0.027169λ² n_e²=4.5820+0.099169/(λ²-0.04443)-0.021950λ²
Nonlinear optical coefficient	d₃₃=34.4pm/V d₃₁=d₁₅=5.95pm/V d₂₂=3.07pm/V
Electro-optical coefficient	g^T₃₃=32pm/V, g^S₃₃=31pm/V g^T₃₁=10pm/V, g^S₃₁=8.6pm/V g^T₂₂=6.8pm/V, g^S₂₂=3.4pm/V
Half-wave voltage DC	Electrical field \|\|z, light⊥z 3.03KV Electrical field \|\|x or y, light \|\|z 4.02KV
Effective nonlinear coefficient	d_eff=5.7pm/V or~14.6xd₃₆(KDP) for frequency doubling 1300 nm; d_eff=5.3pm/V or~13.6xd₃₆(KDP) for OPO pumped at 1300nm; d_eff=17.6pm/V or~45xd₃₆(KDP) for quasi-phase-matched structure;
Damage threshold	200MW/cm²