Nalux Co., Ltd.

Japan Science and Technology Agency

Makoto Okada

Kazuya Yamamoto

Kayoko Fujimura

This invention provides a mold with which a two-dimensional subwavelength grating can be produced with a higher percentage transfer by injection molding and a two-dimensional subwavelength grating having a high aspect ratio produced with such a mold. The mold for a fine grating according to the present invention has protrusion parts () arranged at an interval on the bottom face () of a cavity, wherein the interval is a distance between centers of the protrusion parts and a period of the fine grating smaller than wavelengths of visible lights. In one embodiment, a cross-section of the protrusion parts, parallel to the bottom face of the cavity decreases with height along the protrusion parts and a decreasing rate of the cross-section increases with height along the protrusions.

Fine grating and mold therefor

A polarizing element usable for two wavelengths in a predetermined wavelength region and having a simple structure. The polarizing element has a two-layer structure in which a grid pattern of a constant period &#x39b; having a triangular cross-section is formed on a substrate and a film with a refractive index higher than that of the substrate is deposited on the grid pattern. When first and second wavelengths &#x3bb;, &#x3bb;satisfy &#x3bb;&#x3c;&#x3bb;, &#x39b; cos &#x3b8;&#x3c;&#x3bb;where &#x3b8;is the angle of incidence on the grid surface. The grid period, the grid height, and the film thickness are determined so that with respect to the first wavelength &#x3bb;, the reflection efficiency of the TE-polarized zero-order diffracted light is a predetermined value or more and the transmission efficiency of the TM-polarized zero-order diffracted light is a predetermined value or more and so that with respect to the wavelength &#x3bb;, the transmission efficiency of the TE-polarized zero-order diffracted light is a predetermined value or more and the reflection efficiency of the TM-polarized zero-order diffracted light is a predetermined value or more.

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Osaka, Japan

Makoto Okada