To manufacture a polarization separation element utilizing a photonic crystal polarizer.
Undulate transparent thin films 1 having different refractive indexes 11 are alternately laminated on a slope in a glass board 1 that is formed in a wedge shape to form a polarizer 13. When a wedge angle is set to be θand light is applied from a side where no polarizers are formed, an incident angle to the polarizer becomes θ. TM polarization is transmitted through the polarizer, but is refracted and exits in the direction of 1. When the refractive index of air is set to be n0 and that of the board is set to n, 1=sin-1(nsinθ/ n0)-θ results. Conversely, TE polarization is reflected by the polarizer, reaches the rear surface of the board 10, and is refracted for exiting. In this case, the TE polarization enters the rear surface at an incident angle of 2θ, an emission angle 2 becomes sin-1(nsin2θ/n0). As a result, an angle formed by two emission light can be controlled by the values of the refractive index (n) of the board and the wedge angle θ. For example, two beams orthogonally cross each other by setting to n=1.5 and θ=20°.
SATO TAKASHI
ISHIKAWA OSAMU
KAWAKAMI SHOJIRO
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