Patent ID: 7842924

Claim:
An infrared detector comprising: a reflection portion which transmits rays in the far-infrared range and in the middle-infrared range and which reflects rays in the near-infrared range and in the visible range; a photo-current generating portion having a quantum well structure in which electrons are excited by the rays in the far-infrared range and in the middle-infrared range having passed through the reflection portion and in which the electrons thus excited generate photo-current; a light emitting portion having a quantum well structure into which electrons of the photo-current generated by the photo-current generating portion are injected and in which the electrons thus injected thereinto are recombined with holes so as to emit rays in the near-infrared range and in the visible range; and a photo-detecting portion which detects the rays in the near-infrared range and in the visible range emitted from the light emitting portion and which detects the rays in the near-infrared range and in the visible range emitted from the light emitting portion and reflected by the reflection portion, wherein at least the reflection portion, the photo-current generating portion, and the light emitting portion are made of group III-V compound semiconductors that are layered on top of a substrate, and incident rays in the far-infrared range and in the middle-infrared range are detected by the detection, performed by the photo-detecting portion, of the rays in the near-infrared range and in the visible range emitted from the light emitting portion.