Patent ID: 7705306

Claim:
An infrared photodetector comprising: an isolated two-dimensional electron layer electrically isolated from its surroundings for creating electrons excited upon absorbing incident infrared photons, means for focusing the incident infrared photons upon said isolated two-dimensional electron layer, means for setting free the electrons excited by absorbing the infrared light to escape from said isolated two-dimensional electron layer, thereby to charge said isolated two-dimensional electron layer, and a charge sensitive transistor in which change in current occurs when said isolated two-dimensional electron layer is charged and is maintained while said isolated two-dimensional electron layer is being charged, characterized in that said infrared photodetector includes means for focusing incident infrared photons upon said isolated two-dimensional electron layer and further for creating an oscillatory electric field component for incident infrared photons, perpendicular to a plane of the isolated two-dimensional electron layer, thereby selectively bringing about a two-dimensional intersubband excitation for electrons in said isolated two-dimensional electron layer.