Abstract: A method of producing a diffraction grating of borosilicate glass or barium borosilicate glass, the method comprising the steps of forming a grating on a surface of a silicon wafer the grating through the Bosch process; forming an oxide film on a surface of the grating by heating and exposure to water vapor of the silicon wafer; removing the oxide film using hydrofluoric acid; making the surface provided with the grating of the silicon wafer and a surface of a glass plate undergo anodic bonding; heating the silicon wafer and the glass plate bonded to each other; polishing a surface opposite to the boded surface of the silicon wafer and a surface opposite to the boded surface of the glass plate; and removing silicon from the glass plate by selective etching using xenon difluoride.

Abstract: In order to achieve highly dispersive spectrometry in wide wavelength with the use of a single grism, but not a plurality of grisms, the grism is composed of a prism the vertex angle of which can be varied and a volume phase holographic (VPH) grating. More specifically, the grism comprises a prism the vertex angle of which can be varied; and a VPH grating being a diffraction grating and disposed substantially orthogonal with respect to a side including the vertex angle of the prism; the VPH grating being rotated around an axis being substantially orthogonal to the side of the prism, whereby a slope angle defined by the VPH grating and a predetermined plane is varied.

Abstract: In order to achieve highly dispersive spectrometry in wide wavelength with the use of a single grism, but not a plurality of grisms, the grism is composed of a prism the vertex angle of which can be varied and a volume phase holographic (VPH) grating. More specifically, the grism comprises a prism the vertex angle of which can be varied; and a VPH grating being a diffraction grating and disposed substantially orthogonal with respect to a side including the vertex angle of the prism; the VPH grating being rotated around an axis being substantially orthogonal to the side of the prism, whereby a slope angle defined by the VPH grating and a predetermined plane is varied.

Abstract: A voltage is applied between a cylindrical cutting grindstone 2 that rotates about a vertical axis Y and a cylindrical truing grindstone 6 that rotates about a horizontal axis X. The vertical outer surface 2a and the horizontal lower surface 2b of the cutting grindstone are trued by a plasma discharge. Then without applying the voltage, the cutting grindstone 2 is trued mechanically by the truing grindstone 6, and while the outer periphery and lower surface of the cutting grindstone are dressed electrolytically, the outer periphery and lower surface are made to contact a workpiece 1 and process a micro-V groove. This method makes it possible to produce an immersion grating with a high resolution using hard, brittle materials such as germanium, gallium arsenide and lithium niobate.

Abstract: In order to provide a grism wherein even if the vertex angle of a prism increases, it does not exceed its critical angle, besides, which can elevate its efficiency, and mass-production of which is possible, whereby reduction in cost of which can be realized. The grism comprises a first prism having a high refractive index, a second prism having a high refractive index, and a volume phase grating used for a diffraction grating; and the vertex angle of the first prism being opposed to the vertex angle of the second prism so as to sandwich the volume phase grating between the first prism and the second prism.

Abstract: In order to provide a grism wherein even if the vertex angle of a prism increases, it does not exceed its critical angle, besides, which can elevate its efficiency, and mass-production of which is possible, whereby reduction in cost of which can be realized. The grism comprises a first prism having a high refractive index, a second prism having a high refractive index, and a volume phase grating used for a diffraction grating; and the vertex angle of the first prism being opposed to the vertex angle of the second prism so as to sandwich the volume phase grating between the first prism and the second prism.

Abstract: A voltage is applied between a cylindrical cutting grindstone 2 that rotates about a vertical axis Y and a cylindrical truing grindstone 6 that rotates about a horizontal axis X. The vertical outer surface 2a and the horizontal lower surface 2b of the cutting grindstone are trued by a plasma discharge. Then without applying the voltage, the cutting grindstone 2 is trued mechanically by the truing grindstone 6, and while the outer periphery and lower surface of the cutting grindstone are dressed electrolytically, the outer periphery and lower surface are made to contact a workpiece 1 and process a micro-V groove. This method makes it possible to produce an immersion grating with a high resolution using hard, brittle materials such as germanium, gallium arsenide and lithium niobate.