Process for producing single crystal of potassium niobate

摘要

There has been provided by the present invention a process for producing a single crystal of potassium niobate which comprises disposing a positive electrode directly or via a semi-insulating substance layer on one c-plane of a single crystal of potassium niobate and also a negative electrode via a semi-insulating substance layer on the other c-plane of the single crystal of potassium niobate, said positive and negative electrodes being disposed in mutually facing relationship, and applying voltage between the positive and negative electrodes so as to poll (convert to the single-domain state) the single crystal of potassium niobate, and which enables to poll the entire region of the single crystal of potassium niobate without quality deterioration.