OPTICAL ELEMENT, ILLUMINATION DEVICE, IMAGE DISPLAY DEVICE, METHOD OF OPERATING OPTICAL ELEMENT

摘要

Provided is an optical element that highly efficiently radiates light with high directivity at low etendue. The optical element includes a light emission layer (103) generating an exciton to emit light, a plasmon excitation layer (105) having a higher plasma frequency than a light emission frequency of the light emission layer (103), an output layer (107) converting light or a surface plasmon generated on an upper surface of the plasmon excitation layer (105) into light with a predetermined output angle to output the light, and a dielectric layer (102). In the optical element, a real part of an effective dielectric constant with respect to the surface plasmon is higher in an upper side portion than the plasmon excitation layer (105) than in a lower side portion than the plasmon excitation layer (105); a dielectric constant with respect to the light emission frequency of the light emission layer (103) is higher in a lowest layer than in a layer adjacent to a lower side of the plasmon excitation layer (105); and assuming that a radiation angle of a surface plasmon-derived highly directional radiation from the plasmon excitation layer (105) to the output layer (107) side is θout,spp and a radiation angle of an optical waveguide fundamental mode-derived highly directional radiation is θout,light, an absolute value of a difference between the θout,spp and the θout,light is less than 10 degrees.

主权项

1. An optical element comprising: a light emission layer, a plasmon excitation layer, an output layer, and a dielectric layer, wherein the light emission layer generates an exciton to emit light; the plasmon excitation layer is arranged on an upper side than the light emission layer and has a higher plasma frequency than a light emission frequency of the light emission layer; the output layer is arranged on an upper side than the plasmon excitation layer and converts light or a surface plasmon generated on an upper surface of the plasmon excitation layer into light with a predetermined output angle to output the light; the dielectric layer is arranged at least one of on a lower side than the light emission layer and between the light emission layer and the plasmon excitation layer; a real part of an effective dielectric constant with respect to the surface plasmon is higher in an upper side portion than the plasmon excitation layer than in a lower side portion than the plasmon excitation layer; a dielectric constant with respect to the light emission frequency of the light emission layer is higher in a lowest layer than in a layer adjacent to a lower side of the plasmon excitation layer; and assuming that, in a highly directional radiation from the plasmon excitation layer to the output layer side, a radiation angle of a surface plasmon-derived highly directional radiation is θout,spp and a radiation angle of an optical waveguide fundamental mode-derived highly directional radiation is θout,light, an absolute value of a difference between the θout,spp and the θout,light is less than 10 degrees.