Nalux Co., Ltd.

Masato Okano

Daisuke Seki

Yukinobu Nishio

Kazuya Yamamoto

Kayoko Fujimura

Tomohito Kuwagaito

Makio Nishimaki

Toru Inomata

A diffusion element is configured by combining: a structure for diffusion constituted by combining periodic surface structures having multiple periods to achieve a light intensity distribution in which the light intensity is uniform at angles less than or equal to a predetermined diffusion angle &#x3b8; and the light intensity is as close as possible to zero intensity at angles greater than the diffusion angle &#x3b8;; and a diffractive structure having a period of 1 or more and 2 or less times of &#x39b;max, where &#x39b;max is the maximum period of the structure for diffusion.

Diffuser

A diffuser provided with plural shapes obtained by translation on an xy plane of at least one of z=g(x, y) and z=&#x2212;g(x, y), z=g(x, y) being a smooth function within a rectangle having sides of length of s in x direction and sides of length of t in y direction, the origin being the center of the rectangle, wherein on the sides of the rectangle, and wherein z=g(x, y) has a single vertex at()()=()&#xb7;(),first derivative of()is continuous in second derivative of()has a single point of discontinuity in first derivative of()is continuous in and second derivative of()has a single point of discontinuity in 

A microlens array includes N microlenses arranged in a predetermined direction on an x-y plane. A projection onto the x-y plane of the vertex of each microlens is arranged in the vicinity of a lattice point of a reference lattice on the x-y plane, the lattice spacing of the reference lattice in the predetermined direction being D/M (millimeters) where M is a positive integer. A distance between two sides of a lens facing each other is approximately equal to D, and a distance between the projection onto the x-y plane of the vertex of the lens and the projection onto the x-y plane of a side of the lens is D/2+&#x3b5;i. Letting n represent the refractive index of the material of each microlens and letting f (millimeters) represent the focal length of each microlens, the following relationships are satisfied. 

Microlens array and optical system including the same

A terahertz electromagnetic wave generating element can include a generation layer, and a plurality of pairs of layer structures provided on opposite sides thereof. The layer structures are each provided with a first layer, a second layer on the side of the first layer opposite to the generation layer, and a first grating and a second grating, and having a grating period smaller than the wavelength of the terahertz electromagnetic wave to be used. The first and second gratings are configured so that the refractive index of a medium between the first layer and the second layer continuously varies between a first refractive index and a second refractive index. The thickness of the first and second layers and the grating period, and the grating height are determined so that a terahertz electromagnetic wave having a desired bandwidth with respect to a central wavelength of the terahertz electromagnetic wave generated by the generation layer can be generated.

Terahertz electromagnetic wave generating element

A wavelength filter, includes a grating in which a first portion extends in X direction on a substrate surface and a second portion extends in the X direction along the first portion and are alternately arranged in Y direction perpendicular to the X direction on the substrate surface at a constant cycle shorter than a wavelength of light to be used. A cross-sectional figure of respective first portions in the Y direction and perpendicular to the substrate surface is provided with at least one protruding portion so as to have the width in the Y direction wider than neighboring portions. Plural waveguide layers parallel to the substrate surface are divided by regions parallel to the substrate surface. Wavelength bands of light reflected from the plural waveguide layers shift while overlapping with each other to reflect a wavelength band broader than that reflected from a single waveguide layer.

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Osaka, Japan

Masato Okano