Shimadzu Corporation

Japan Atomic Energy Research Institute

Yoshihisa Harada

Masato Koike

Kazuo Sano

Akihiro Arai

Ryo Tateno

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

A Czerny-Turner spectroscope according to the present invention includes: a collimator mirror having a toroidal surface for reflecting a beam of light passing through an entrance slit to a plane diffraction grating; and a telemeter mirror having a cylindrical surface for reflecting and converging the beam of light reflected and separated by the plane diffraction grating to an exit. When a slit is placed at the exit, the straight generatrix is set substantially parallel to the exit slit. When a linear object (such as the separation channel of the capillary electrophoresis microchip) to receive a part of the spectrum of light reflected by the telemeter is placed at the exit, the linear object is set parallel to the straight generatrix. By this construction and configuration, the curving of monochromatic spectrum component at the exit is minimized, and the monochromatic light produced by the inventive Czerny-Turner spectroscope can pass the exit slit in full. Thus, when used, as the detector of a capillary electrophoresis microchip, stability and reproducibility of capillary electrophoresis measurements are achieved.

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Shiga-ken, Japan

Yoshihisa Harada