Abstract:
The invention concerns a system for achieving an optical image of an object (136), and/or for achieving optical collimation (137) of light from a light source (130), comprising a concave mirror (131: 134), the surface normal of which forms an angle with the incident light in a beam. A negative lens (132, 133) that co-operates with the concave mirror is arranged in the incident and/or exit beam paths such that an image with eliminated or reduced imaging aberrations is achieved in a focal plane (135), and/or that the exit light from a light sources (130) is collimated (137).
Abstract:
An apparatus for carrying out spectral analysis of optical radiation emitted from a light source (11) comprises a spectral detector (1) having an entrance aperture (10) for the radiation from thelight source (11), a first imaging optical component (11), a first imaging optical component (12), a diffraction grating (14) for wavelength dispersion of the radiation, order sorting means (131, 132) for separation of the spectral orders of the diffraction grating (14), a second imaging optical component (15), and a detecting unit (16) for registration of the light source spectrum divided into order spectra through the order sorting means (131, 132). The order sorting means (131, 132) comprise at least two refractive optical components manufactured from different material. The two refractive optical components (131 and 132) together with the diffraction grating (14) and the imaging optical components (12 and 15) produce a substantially uniform distribution of the order spectra on the detector unit (16). Favourably the order sorting means (131, 132), the diffraction grating (14) and the imaging optical components (12, 15) also co-act to produce a substantially stigmatic image of the entrance aperture (10) in at least one point on the detector unit (16).
Abstract:
To eliminate astigmatism and coma in a spectrograph the distance between the entrance slot and a first concave mirror, as well as the relative angular positions of the entrance slot, the plane grating, the two concave mirrors and the focal plane are selected so as to satisfy the following conditions. ##STR1##