OPTICAL ELEMENT, OPTICAL HEAD USING THE SAME, AND OPTICAL RECORDING AND REPRODUCING DEVICE

摘要

PROBLEM TO BE SOLVED: To provide an optical element which achieves the suppression of an increase in light power and temperature rise by utilizing surface plasmon enhancement effect using a conductive film in which a subwavelength aperture and surface topography are formed.

SOLUTION: The subwavelength aperture 40 is formed on the conductive film 30 and further, the periodic surface shapes 31 are formed thereon. Incident light is condensed by a lens 10 at a prescribed diameter r to the shapes 31. The light emitted from the aperture 40 at the center of the film is intensified by the surface plasmon mode excited by the incident light. The prescribed diameter r of the incident light and the period a of the periodic surface topography are so determined that the ratio of the light power and the power of the light emitted from the aperture is made higher than the ratio of the similar light power in the optical element not having the surface topography.

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