Optical formation of photonic waveguides and circuits in ferroelectric lithium niobate due to the contribution of pyroelectric effect

The pyroelectric nonlinear response of nominally undoped lithium niobate crystal is exploited to form within it as single waveguide channels as more complicated waveguide structures suitable for the photonic applications. The light wavelength of 532 nm with optical powers lower than 1 mW allowed their formation in experiments.