Nanosecond Laser-Induced Plasma Radiation And Its Interference With CCD Detectors

Laser plasma has a wide wave band of electromagnetic radiation,including electromagnetic emission from extreme ultraviolet to the microwave.Optical radiation(visible and infrared wavelengths)and RF radiation of laser plasma can interfere with the optical imaging and imaging detection circuitry of photoelectric detection instruments such as charge couple device(CCD).Therefore,it is of great significance to study the influence of laser parameters on the characteristics of plasma radiation and RF electromagnetic emission,and the interference mechanism of laser plasma radiation impacting on CCD detectors.The research results can provide certain experimental methods for the photoelectric imaging device to resist the interference of plasma radiation,and have important application reference value for improving the optoelectronic countermeasure capability.In this paper,the radiation characteristics based on nanosecond laser-produced and its interference with CCD detectors were mainly studied.The characteristics of laser plasma visible radiation,infrared radiation,and RF radiation were obtained.The experimental study on the radiation of nanosecond laser-produced plasma interfering with CCD detectors was carried out.And the interference mechanism of plasma radiation impacting on the CCD detector was obtained.The main contents and research results of the paper are as follows:(1)The characteristics of nanosecond laser-induced plasma optical radiation(visible light,infrared)were studied.The influence of the laser parameters on the plasma radiation intensity and the time evolution of the radiation were obtained,furthermore,the effect of the characteristics of the target on the radiation characteristics of the plasma were also obtained.(2)The radio-frequency(RF)emissions in the range from 30 MHz to 800 MHz based on the plasma,which is produced by the nanosecond laser induced breakdown of atmospheric air are presented.RF electromagnetic radiations from the laser induced breakdown atmospheric air for different input laser energies are obtained.The spatial distribution of plasma RF radiation depends on the polarization of the input laser.It is observed that the total power of RF radiation first increases and then decreases with the increase of input laser energy.And the influence of the characteristic parameters of the target on the characteristics of plasma RF electromagnetic radiation was obtained.(3)The characteristics of the radiation of nanosecond laser-produced plasma interfering with CCD detectors were studied.The interference graphs of plasma radiation to CCD detectors under different laser power densities were obtained.The interference area and the ratio of pixels to laser power density were obtained.Moreover,the interference mechanism of laser plasma radiation on visible light area array CCD was analyzed.