Lithium Niobate (LiNbO3 or LNB) and Lithium Tantalate (LiTaO3 or LTA) possess a combination of unique electro-optical, acoustic, piezoelectric, pyroelectric and non-linear optical properties making it a suitable material for applications in acoustic, electro-optical and non-linear optical devices, high-temperature acoustic transducers, receivers-transmitters of acoustic vibrations, air force acceleration meters, acoustic wave delay lines, deflectors, generators of non-linear distorted waves, acoustic filters, electro-optical Q-modulators (Q-switch), encoders-decoders, filters in television receivers, video-recorders and decoders, converters, frequency doublers and resonators in laser systems, non-linear elements in parametric light generators, etc. An indispensable condition of some of these applications is a high degree of optical uniformity of Lithium Niobate crystals used for fabrication of active elements. Crystal growth technology by low temperature-gradient Czochralsky method allows the growth of large-size high-quality LNB (up to 1-1.5 kg) and LTA single crystals for such non-conventional applications. It should be noted that both crystals are non-hygroscopic, colourless, water-insoluble and have low transmission losses.
LiNbO3 damage due to photorefractive effect in congruent melt grown LiNbO3 certainly limits it's applications in high optical power devices. For this purpose specially grown LiNbO3 with composition near stoichiometric can be offered. It is similar to the Li-rich VTE LiNbO3 with the obvious advantage that bulk samples can be obtained. Another possibility to increase laser damage threshold of LiNbO3 is doping with MgO. MolTech can offer both MgO:LiNbO3 and stoichiometric LiNbO3 elements cut from boules up to 60 mm dia.
Some other crystals of LiNbO3 series are available, including LiNbO3 doped with Fe, Zn, Gd, Cu , Y, B, Er etc.
For some applications similar in properties to Lithium Tantalate (LiTaO3) crystal is more advantageous than LiNbO3 (E-O modulators, pyroelectric sensors etc.). Lithium Tantalate exhibits unique electro-optical, pyroelectric and piezoelectric properties combined with good mechanical and chemical stability and wide transparency range and high optical damage threshold. This makes LiTaO3 well-suited for numerous applications including electro-optical modulators, pyroelectric detectors, optical waveguide and SAW substrates, piezoelectric transducers etc. MolTech can offer parts cut from high quality boules grown along X axis, fully poled, with dia. and length of up to 60 mm.
|Transparency range, µm||0.4 - 5||0.4 - 5|
|Lattice parameters (hexagonal), Å||a = 5.148, c = 13.863||a = 5.154, c = 13.784|
|Refractive indexes :||no = 2.28647, ne = 2.20240 (at 0.633 µm)||no = 2.183, ne = 2.188 (at 0.6 µm)|
| ||no = 2.2273, ne = 2.1515 (at 1.1523 µm)||no = 2.131, ne = 2.134 (at 1.2 µm)|
|Non-linear coefficient at 1.06 µm, pm/V||d22 = 5.6, d31 = -11.6, d33 = 8.6||d22 = 2, d31 = -1, d33 = -21|
|Electroptical coefficient at 0.63 µm, pm/V||r31 = 8.6, r22 = 3.4, r33 = 30.8, r51 = 28||r13 = 8, r22 = -0.2, r33 = 30|
MolTech provides LiNbO3 and LiTaO3 crystals with high optical quality as finished wafers, elements or blanks at your request. Orientation, polishing, single-band and dual-band AR-coatings by customers' order. The AR-coatings are characterized by low reflectance, high damage threshold and long durability.