Lithium niobate is a ferroelectric material with excellent electro-optic, nonlinear optical, and piezoelectric properties. It is one of the most thoroughly characterized electro-optic materials, and Inrad Optics’ crystal growing techniques consistently produce large lithium niobate crystals of exceptional quality. Lithium niobate has a broad transmission range from the visible to the mid-infrared and can be used for a variety of electro-optical and nonlinear optical applications.
Optical modulation and Q-switching. Thanks to its large electro-optic coefficients, lithium niobate is well suited to optical modulation and Q-switching of infrared wavelengths. Among its advantages in these applications are its low half-wave voltage and zero residual birefringence.
Nonlinear optical frequency conversion. Tunable wavelengths can be generated in lithium niobate over a broad range via phasematching processes. Lithium niobate can generate tunable infrared output via difference frequency mixing processes. For second harmonic generation of Nd:YAG lasers at 1.064 µm and low power laser diodes between 1.3 µm and 1.55 µm, lithium niobate is a highly efficient crystal.
Optical Design Notes
- Consider using magnesium oxide doped lithium niobate (MgO:LiNbO3) for higher power applications. The addition of 5 mol% magnesium oxide (MgO) to lithium niobate produces material with significantly improved optical and photorefractive damage resistance. MgO doped lithium niobate is useful for high power laser applications. Inrad Optics offers MgO:LiNbO3 grown along the crystallographic x, y, or z axes in lengths up to 40 mm.
- Consult the Inrad Optics white paper on electro-optic behavior for background information on the use of lithium niobate.
| Material Properties | ||
| Composition | Congruent, 48.38 mol % Li2O | |
| Crystal Symmetry and Class | trigonal, R3c Point Group 3m | |
| Lattice Parameters | a = 5.15052 Å | |
| c = 13.86496 Å | ||
| Density | 4.648 g/cm3 | |
| Mohs Hardness | 5 | |
| Optical Class | Uniaxial negative | |
| Transmission Range | 0.400 μm - 5.0 μm | |
| Thermal Conductivity @ 27 °C | κ = 4.2 W/m·K | |
| Thermal Expansion | αa = 14.1 x 10-6 /K | |
| αc = 4.1 x 10-6 /K | ||
| Electro Optic Coefficients @ 0.633 μm T: unclamped |
r13T = 10 pm/V r22T = 7 pm/V |
r13S = 9 pm/V r22S = 3 pm/V |
| r33T = 33 pm/V r51T = 33 pm/V |
r33S = 31 pm/V r51S = 28 pm/V |
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Dimensions
Typical apertures range from 3 mm up to 12 mm, but larger apertures are available on request. Available thicknesses range from 0.5 mm to 30 mm.
Finishing
- Dielectric AR coating
- Electrodes for Q-switching
- Ring mounts compatible with standard optomechanics
Orientations
Standard cuts are available for OPO crystals, Q-switch elements, difference frequency mixing crystals and autocorrelation crystals.
Configuration Options
| Designation | Angle, θ | Operation | Input | Output |
| "A" | 68.8° | DFM | (564-600 nm) - 1064 nm | 1200-1380 nm |
| "B" | 59.6° | DFM | (600-664 nm) - 1064 nm | 1370-1770 nm |
| SHG | 1310 nm | 655 nm | ||
| "C" | 46.8° | DFM | (664-923 nm) - 1064 nm | 1770-4000 nm |
| SHG | 1550 nm | 775 nm | ||
| "D" | 47° | DFM | 1064 - (1450-2000 nm) | 2300-4000 nm |
| OPO | 1064 nm | 1450-4000 nm | ||
| "QS" | Z | Q-Switch |