Abstract: A diode array spectrophotometer has an entrance slit apparatus, a diffraction grating, a diode array and a casing to define the relative positions of the elements. The casing and the holder for accepting the diffraction grating are made of a ceramic whose coefficient of thermal expansion is matched to that of the diode array. The grating holder has a cylindrical outer surface and is situated within a conic-frustum-shaped opening of the casing. Between the grating holder and the conic-frustum-shaped opening, there are a plurality of filler elements which are made of ceramic or glass.

Abstract: An adjustable optical component, for example an optical slit having adjustable slit width, comprises a movable member for providing an optical function, for example a slit and/or a shutter, and resilient suspension elements for connecting the movable member to a frame. The essential parts of the movable member, of the resilient suspension elements and of the frame consist of microstructures which are made of a common base material. Preferably, these parts are manufactured from a silicon chip by a micromechanical technique comprising, for example, anisotropic etching. In the case of an optical slit, the movable member comprises a plurality of openings of different widths which constitute a step slit. In order to adjust different slit widths, the member is moved along a line parallel to the center line of the step slit, with the force for moving the member being applied at an opening. When the member is moved by an external force, the resilient silicon beams are bending and the bars are moving.

Abstract: A photodiode array spectrometer for determining the spectral composition of a plychromatic beam of radiation comprises diffraction means (10) which generate from the polychromatic beam a diffracted beam with a plurality of spatially separated diffracted rays of different wavelengths (.lambda..sub.1, .lambda..sub.2, .lambda..sub.3). A photodiode array (11) receives the diffracted beam whereby each photodiode intercepts a different spectral portion of the beam. A rotatable transparent plate (8) is provided in the beam path in front of the diffraction means (10) which, due to refraction of the beam upon entering and leaving the plate (8), permits to vary the direction of the beam impinging on the diffraction means (10) and therefore the direction of the diffracted beam in small steps depending on the angle of rotation of the plate (8).