A monochromator comprises a first and a second concave grating. An entrance slit is imaged by the concave grating in the plane as a spectrum. A disc comprises a spiral slot. A section of the slot forms an intermediate slit periodically sweeping transversely across the spectrum. A concave mirror images the fanning point of the concave grating. Thereby the fanned beams are recombined to a single beam. An exit slit is located in an image plane in which an image of the entrance slit is generated. The spectrum can be scanned quickly and cyclically without the gratings having to be rotated. There is also the effect of a double monochromator. Another embodiment comprises two concave mirrors to generate the image.

A device for the adjustable coupling of wavelengths or wavelength regions into the illumination beam path of a microscope, preferably in the beam path of a confocal microscope, comprising at least one dispersive element for wavelength separation of the illumination light and at least one at least partially reflecting element arranged in the wavelength-separated portion of the illumination light for reflecting back a wavelength region in the direction of the microscope illumination, and a device for the adjustable detection of object light coming from an illuminated object, preferably in a microscope beam path, comprising at least one dispersive element for wavelength separation of the object light and means arranged in the wavelength-separated portion of the object light for the adjustable stopping down or cutting out of at least one wavelength region and deflection in the direction of at least one detector.

The filtration means filter the exciter radiation (EX) in a first forward direction from generator means (LS) to the specimen (EC), by allowing a second spectral band (BZ) of predetermined spectral width (l) and centered on a selected frequency corresponding to the wavelength of the exciter radiation (L0) to pass and stopping a first spectral band (FZ) complementary to the second spectral band (BZ), while substantially simultaneously with this first filtration operation, these filtration means further filter the analysis radiation (ON) in a second direction that is the reverse of the first direction, by allowing the first spectral band (FZ) to pass and stopping the second spectral band (BZ).

A method and apparatus for controlling the spectral components of a light beam are described. The apparatus comprises means (3-7) for generating a collimated light beam; means (9) for dispersing the collimated beam; a mask (1) including an aperture (2) the size of which is such that a portion of the dispersed beam passes through the aperture in use; and movement means (not shown) for causing relative transverse movement between the light beam and the aperture. A memory (not shown) is provided for storing in use a profile of the relative transverse movement between the light beam and the aperture (2) required to obtain a desired spectral response in the transmitted light beam, the movement means being responsive to the stored profile to cause relative transverse movement in accordance with the predetermined profile.

Color is synthesized by dispersing a beam of light to form a spectrum, effectively blocking a portion of the spectrum with a mask, and recombining the light energies of the unblocked portion(s) of the spectrum to synthesize the color.