| 摘要 |
<p>This photodetector (1A) is provided with: an optical element (10) which has a structure including first regions, and second regions periodically arranged with respect to the first regions, along a perpendicular surface, in a prescribed direction, and which generates an electric field component in a prescribed direction when light is incident along a prescribed direction; and a semiconductor stacked body (4) which is disposed on another side of the optical element (10) in a prescribed direction, said other side being opposite to one side of the optical element (10) in the prescribed direction, and which has a quantum cascade structure for generating electric current using the electric field component in the prescribed direction generated by the optical element (10). The quantum cascade structure includes: an active region (4b) having a first quantum upper level, and a second quantum upper level lower than the first quantum upper level; and an injector region (4c) for transporting electrons excited by the active region (4b).</p> |
