Lithium niobate (_LiNbO3) has a combination of unique electro-optical, acoustic, piezoelectric and non-linear optical properties with mechanical and chemical stability.

Lithium niobate is highly birefringent, has no inversion symmetry and exhibits the Pockels effect. Its birefringence is strongly dependent on temperature. Therefore, phase matching in the medium can be achieved by increasing the temperature. It has large effective nonlinear, electro-optic and battery-optic coefficients.

Lithium niobate is widely used in electro-optic, battery-optic and non-linear optical devices, Pockels cells, optical parametric oscillators (OPO), optical switches in the GHz frequency range, high-temperature transducers, receivers and transmitters of acoustic oscillations, laser frequency doubling and Q-switch devices for lasers.

Transverse modulation is mostly used for lithium niobate crystals as frequency doublers for wavelengths >1µm and OPO pumped at 1064nm as well as for quasi-phase-matched frequency doublers.