OPTICAL ELEMENT, LIGHTING DEVICE, AND PROJECTION TYPE DISPLAY DEVICE

摘要

Provided is an optical element that can solve the problem of increasing étendue when converting random polarization to a specific polarization state. A first plasmon excitation layer (24) that excites first surface plasmons by a specific polarization component out of light incident from a light guide layer (21) has metal parts (31) and dielectric parts (32) that extend in a first direction within the interface with the light guide layer (21) and are disposed alternately and periodically in a second direction orthogonal to the first direction. In addition, a second plasmon excitation layer (25) that excites second surface plasmons corresponding to the first surface plasmons and generates light that has a specific polarization component from the second surface plasmons has metal parts (41) and dielectric parts (42) that extend in the first direction and are disposed alternately and periodically in the second direction in the same periods as the metal parts (41) and the dielectric parts (42).