Determination of depth of proton exchanged layer in LiNbO3 from laser induced pyroelectric signals

A new nondestructive technique for the determination of the depth of the proton exchanged (PE) layer in LiNbO₃ is reported. The techniques relies on the difference in phase of measured pyroelectric voltages, induced by a modulated laser beam incident on the exchanged and unexchanged regions. Measurements of PE layer thickness in a Z-cut LiNbO₃ sample have been corroborated by prevalent, more elaborate, optical characterisation techniques.