Optical diffraction device and optical information processing device

摘要

The present invention is an optical diffraction element to be disposed in an optical path through which a plurality of light beams of different wavelengths travel. It has a periodic structure which, when a first light beam having a wavelength lambda₁ among the plurality of light beams is in a linear polarization state polarized in a first direction X, allows the first light beam to be substantially completely transmitted therethrough, but when the first light beam is in a linear polarization state polarized in a second direction Y perpendicular to the first direction, causes the first light beam to be substantially completely diffracted. At least a portion of a second light beam having a wavelength lambda₂ among the plurality of light beams, the wavelength lambda₂ being different from the wavelength lambda₁ of the first light beam, is diffracted regardless of the polarization state thereof.