When light is incident to an antenna layer AA6 of a photocathode AA1, light of a specific wavelength included in the incident light couples with surface plasmons in the antenna layer AA6 whereupon near-field light is outputted from a through hole AA14. The intensity of the output near-field light is proportional to and greater than the intensity of the light of the specific wavelength. The output near-field light has a wavelength that can be absorbed in a photoelectric conversion layer AA4. The photoelectric conversion layer AA4 receives the near-field light outputted from the through hole AA14. A region of the photoelectric conversion layer AA4 around the through hole AA14 absorbs the near-field light and generates photoelectrons (e−) in an amount according to the intensity of the near-field light. The photoelectrons (e−) generated in the photoelectric conversion layer AA4 are outputted to the outside.