Optical component of a satellite laser ranger for multi-color range finding

The optical cluster of a satellite laser range is used for the next goals: to expand laser beams, registering the laser impulses reflected from the satellite and visual observing of the satellite. The perspective decision for these purposes is a combined optical scheme. The purpose of the research was to calculate the optical cluster of the satellite laser ranger. The expander of the laser beam works at the same time for a wide range of wavelengths without any additional refocusing. A laser beam expander is a catadioptric system with the entrance pupil diameter about 42 mm and approximately 300 mm outlet. The optical system of the expander of laser beam for the satellite laser ranging station in the optical and near infrared wavelengths is presented. The collimation of the laser beam takes place in the expander without any additional refocusing for wavelengths from 435 to 2098 nm with a sevenfold increase. The beam divergences for monochromatic radiation are defined as well. In the reverse ray path the expander can be the feeding optics of object tracking lens in the optical range. To avoid vignetting when using the expander as feeding optics of CCD-camera for the satellite tracking (in the reverse ray path), the light lens diameters are calculated. The authors presented two options of a lens of camera: lens containing usual optical glass and lens containing optical glass with special dispersion path: special crown (OK4) and special flint (OF1). Equivalent focal length of a lens is ~ 1760 mm. In the article the analysis of the RMS spot diameter and radial energy distribution of spot has been shown. In the presented optical system Coudě focus is used which allows using the equipment installed permanently. When calculating the optical system, the radii of curvature of all spherical surfaces are recommended by All Union State Standard 1807-75 which reduces the cost of manufacturing technology. The expander of laser beam may be used for satellite laser ranging station and laser radars on the Earth surface.