Infrared Wavelength Tuning by Laser Irradiation of an Ultrathin Silicon Plate

Abstract

Fabry–Pérot filters were fabricated with Si plates of 13–30 µm thickness, and the feasibility of all-optical wavelength tuning was examined. These thin Si plates exhibited pronounced interference peaks over a wide infrared wavelength region (4–16 µm). The peaks shifted to longer wavelengths by 0.1–0.2 µm, when a Si plate was exposed to a light beam from a laser diode of 0.94 µm wavelength. It was supposed from the peak shift that the refractive index of the Si plate changed by 2.4% during the laser irradiation process.