Research On Laser Refractive Andscattering Characteristics Of Transmission Imaging Systems

Optical imaging systems have wide applications in guided weapons, satellite reconnaissance, night vision and other military fields, the research on obstruction and damage of optical imaging systems in the field of photoelectric countermeasure has become the focus of information warfare. With its high intensity, high purity, good collimation and quick response, laser is easy to cause obstruction or damage to the optical imaging detector. Before detected by imaging detector, the laser needs to go through the optical imaging system first. Therefore, the research on the energy distribution at the image plane, owing to laser refracted or scattered through an optical system, has important significance. In this thesis, the content is arranged as follows:Firstly, the energy distribution at image plane of laser- incident optical system was studied in this dissertation. To derive the laser transmission theory based on wave optics, we connect the Collins diffraction integral to the ABCD matrix elements. The diffraction integral of complex optical s ystems is derived, which can be used to calculate the energy distribution at image plane owing to Gaussian beams through the optical systems. Based on a real optical system, the energy distribution at image plane is calculated. The laser wavelength is 532 nm and 1064 nm, effective range is 10 m and has a different attenuation rate. The impact to the CCD detector of this case is analyzed. The result shows that the energy of laser transmitted through optical system, with wavelength of 532 nm or 1064 nm, can saturate the CCD.Secondly, the image plane energy distribution caused by the laser oblique incident optical system after being scattered was researched. We analyzed the plane surface energy distribution with using the ray tracing software Trace Pro and the scattering transmission theory. Use the cylinder and stop ’s BRDF to get the ABg elements though data processing and curve fitting. Finally, establish a scattering model aimed at analysis the image plane energy distribution when the laser oblique incident optical system, which wavelength is 532 nm and 1064 nm.In order to verify the accuracy of the calculation when the laser incident optical system, we done the physics experiments and get the image plane energy distribution. The laser ’s wavelength is 532 nm and 1064 nm and attenuation rate is 60 d B and 90 d B. By contrast, we proposed an ideological that is to add a transmission parameter to revise the laser transmission theory. In addition, we simulated and analyzed the number of the saturated pixels on CCD, when the incident angles or the detector saturation threshold are different. At last, we analyze the relationship between the number of the saturated pixels and the incident angles or the detector saturation threshold. The result showed that the wavelength of 532 nm laser can make the detector damage. The wavelength of 1064 nm laser can only make the detector saturation.