摘要 |
An optical element 10 for transmitting light therethrough along a predetermined direction and modulating the light comprises a structure 11 having a first region R1 and a second region R2 periodically arranged with respect to the first region R1 along a plane perpendicular to the predetermined direction, the first and second regions R1, R2 having respective refractive indexes different from each other, and properties of transmitting the light therethrough. |