Subwavelength plasmonic microcavity light coupling structure for promoting photoelectric detector response

The invention discloses a subwavelength plasmonic microcavity light coupling structure for promoting photoelectric detector response rate. The propagation direction and optical field distribution of incident light are modulated through a plasmonic microcavity, thus the incident light is limited to be propagate in the microcavity, the light escape is reduced, and the utilization rate of photons is raised. The incident light is focused in the microcavity such that the intensity is greatly enhanced, and a photoelectric detector with a high response rate can be formed through clamping photoelectric conversion material in the microcavity. The coupling structure is formed by a metal grating layer formed by upper layer periodic metal bars, a photoelectric conversion activation layer and a lower layer metal reflective layer. The subwavelength plasmonic microcavity light coupling structure has the advantages that by using the mode selection effect of an electromagnetic wave near field coupling microcavity formed by plasmonic resonance between the upper layer metal grating and the lower layer metal reflective layer, thus the photons in the microcavity are propagated along a transverse direction to form standing wave, the light field energy is gathered and the length of equivalent optical absorption is increased, and the response rate of the detector is greatly raised.