Tunable lead-chalcogenide on Si resonant cavity enhanced midinfrared detector

Midinfrared tunable resonant cavity enhanced detectors have been realized. The linewidths of 0.07μm are determined by the finesse of the cavities, while the length of the cavity can be changed with a movable mirror. This allows tuning across the 4–5.5μm midinfrared wavelength range. The thin (0.3μm) photodiodes inside the cavity are based on lead-chalcogenide narrow gap semiconductor layers grown epitaxially onto a Si substrate. Due to the thin active layer, a higher sensitivity at the higher operation temperatures is achieved as compared to conventional thick photodiodes.