| Popis: |
Recently, has come into existence an interest in the systems operating in the ultra-violet (UF) band of wavelengths, which use other spectral information (coefficients of reflection or radiation in UF range) about location objects, than laser systems in the visible, near or average infrared bands. Thus, a point is not only to receive additional (in another spectral range) information on location objects. Laser radiation in the UF spectral band of 0.315 – 0.4 microns is safer than laser radiation with the wavelengths of 0.38 – 1.4 microns.The work presents a comparative estimation of the detection systems range of laser radars in the UV and visible spectral bands for the following wavelengths of radiation:- UF band: 0.266 microns (the fourth harmonic of YAG-laser activated by neodymium ions), 0.308 microns (the XeCl-excimer laser), 0.355 microns (the third harmonic of YAG-laser activated by neodymium ions);- visible band: 0.532 microns (the second harmonic of YAG-laser activated by neodymium ions).Results of calculations show that for the horizontal pathway in the terrestrial atmosphere at the selected radiation wavelengths a detection range is in the range of 2510m – 5690 m.The maximum range of detection corresponds to the visible spectral band. A sweep range decreases with transition to the UF band. This is caused by the fact that with transition to the UF band there is a rise of atmosphere attenuation (generally, because of absorption by ozone), this effect being smoothed by reducing background radiation.In the UF band a wavelength of 0.355 microns is the most acceptable. For this wavelength a detection range is about 1,5 times less (in comparison with the visible band of 0.532 microns). However, this is the much more eye-safe wavelength. With transition to the UV band a detection range decreases not that much and can be compensated by changing parameters of transmitting or receiving channels of laser radar. |
