Shimadzu Corporation

Japan Atomic Energy Research Institute

Tohoku University

Jeol Ltd.

Japan Atomic Energy Agency

Ntt Advanced Technology Corporation

National Institutes for Quantum and Radiological Science and Technology

Masato Koike

Kazuo Sano

Yoshihisa Harada

Hideyuki Takahashi

Masami Terauchi

Hiroyuki Sasai

Takashi Imazono

Hideyuki Noda

Masatoshi Hatakeyama

Masahiko Ishino

Hisataka Takenaka

Nobuyuki Iwai

To cover a wide wavelength bandwidth, a spectroscopic apparatus uses three varied line spacing concave diffraction gratings Gto G, the corresponding energy ranges for G, G, and Gbeing 50 to 200, 155 to 350, and 300 to 2200 eV, respectively. In the respective wavelength ranges, the diffraction conditions are satisfied. To provide a high throughput and a high resolution in the respective wavelength regions, the incident angles &#x3b1;to &#x3b1;for Gto Gmeasured from the normal line of the diffraction grating are specified to be &#x3b1;&#x3c;&#x3b1;&#x3c;&#x3b1;. Presupposing the normal lines of all diffraction gratings are superposed upon a common normal line, in order to meet &#x3b1;&#x3c;&#x3b1;&#x3c;&#x3b1;, the center positions &#x394;to &#x394;for Gto Gare set on the normal line (as &#x394;&#x3c;&#x394;&#x3c;&#x394;). From Gto G, one diffraction grating can be selected.

Spectroscopic apparatus

A conical diffraction grazing incidence spectroscope for performing wavelength scanning by rotating a diffraction grating about an axis set parallel to groves in a grazing surface of the grating.

Conical diffraction grazing incidence spectrometer and diffraction grating for use in the spectrometer

A plane diffraction grating based on surface normal rotation according to the present invention is designed so that the profile of the grooves at a radial area is determined depending on a rotational position of the area about a rotational center defined as a foot of the rotational axis on the surface of the plane diffraction grating. An optical system such as a spectrometer or a monochromator according to the present invention uses such a plane diffraction grating, and requires a special arrangement. The optical system includes: a plane diffraction grating as described above; a mechanism for rotating the plane diffraction grating about the rotational axis; an incidence optical system for casting a converging beam of light on a point of the surface of the plane diffraction grating, where the point is set apart from the rotational center. As the diffraction grating is rotated about the rotational center, the point on which the incident converging beam of light is cast rotates about the rotation center, where the diffracting condition is optimized anywhere around the rotational center or for any scanning wavelength. The surface of the plane diffraction grating can be covered with a multiple-layer coating to improve diffraction efficiency. When such a multiple-layer is coated, the unit thickness of the multiple-layer coating at an area is also determined depending on the rotational position of the area about the rotational center.

Plane diffraction grating based on surface normal rotation and its application to an optical system

In formulating a groove pattern for a diffraction grating by means of holography, unique groove patterns are obtained by use of astigmatic coherent beam as either one or two recording beams. Instead of use of only stigmatic beams, and astigmatism in recording light in manufacture of a halographic grating will bring more utilizable parameters in designing groove patterns by which new loci of the type of non-hyperboloidal curves are formed on grating substrates and thereby elimination of abberations which were conventionally difficult are achieved with various optical devices.

Halographic grating and optical device incorporating the same

A constant deviation monochromator with a holographically formed concave grating and entrance and exit slits positioned on opposite sides of the plane including the Rowland circle of the grating, wherein the grating has been formed by using two coherent light sources positioned on the same side of the Rowland plane, whereby aberrations and stray light are substantially reduced.

Monochromator with concave grating

Growing community of inventors

Kyoto, Japan

Masato Koike