Method of producing quasi phase-matching crystal and quasi phase-matching crystal

Abstract

Rectangular protruding partsare formed on the surface of one side of a quartz crystal substrate; these protruding partsare formed as aggregates of rectangular protruding partsof an even finer pattern. Recessed partswhich are lower than the surfaces of the protruding partsare formed between the protruding parts; however, the width of these recessed partsis narrow, so that when the protruding partsare viewed on the macroscopic scale, numerous protruding partsare aggregated, and appear to form single protruding parts. Such a quartz crystal substrateis clamped between heater blocks from above and below, and the temperature of the quartz crystal substrate is elevated. At the point in time at which this temperature reaches a desired temperature, the substrateis pressed by means of a press. Consequently, stress acts only on the portions corresponding to the protruding parts, so that the crystal axis components are inverted only in these portions. These portions with inverted crystal axes grow into the interior portion of the crystal, and are propagated into the interior portion of the crystal, so that the portions corresponding to the protruding partsare connected, thus forming crystal axis inversion regions. As a result, crystal axis inversion regions with a desired shape can easily be formed.