|
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. 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.
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
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.
<<<Back
|