All-optical technique to measure the pyroelectric coefficient in electro-optic crystals

We report an all-optical method to measure the pyroelectric coefficient p of electro-optic crystals. Through this technique, we first acquire the birefringence variation δΔn of the crystal as a function of its temperature T, both in closed and open-circuit conditions, using a Sénarmont phase-compensation configuration. Then the pyroelectric field is deduced from the difference between these two measurements, so it leads to the material spontaneous polarization change, whose derivative with respect to the temperature finally gives p. This technique is applied on congruent and stoichiometric lithium niobate.