Optical device, a method of manufacturing optical device, and exposure apparatus

A manufacturing method of optical device, comprising:

• a first step of integrating a ferroelectric substrate formed by ferroelectric crystals with a support plate which is thicker than the ferroelectric substrate to support the ferroelectric substrate with the support plate by a conductive junction between one major surface of the ferroelectric substrate and one major surface of the support plate;
• a second step of forming a pattern electrode which has a periodic pattern on the other major surface of the ferroelectric substrate;
• and
• a third step of applying a voltage between the pattern electrode and the junction and forming a periodic domain inverted region in the ferroelectric substrate,
• wherein the first step comprises the steps of:
• forming a first insulation layer on one major surface of the ferroelectric substrate;
• forming a first metal layer on the first insulation layer;
• forming a second metal layer on one major surface of the support plate;
• and
• joining the first metal layer with the second metal layer and accordingly integrating the ferroelectric substrate with the support plate to support the ferroelectric substrate with the support plate.