The imaging systems are widespread observation tools used in the national defense, industry and a number of aspects in science and technology. The CMOS image sensors which serve as the core part of optical imaging systems and detecting systems, are highly susceptible to laser interference and destruction. Therefore, it is of great theoretical and practical significance to study the damage characteristics of CMOS image sensor. There are many researches on the damage phenomena of CMOS image sensors irradiated by continuous laser, ns-laser, ms-laser and fs-laser, but the damage effects of CMOS irradiated by the hundred picoseconds fiber laser are few investigated. In this work, we used an all-fiber MOPA ps-pulsed laser system which generates pulse width of 226.5 ps and average power of 20 W with high beam quality and pulse stability to irradiate the CMOS at repetition rate of 9.6 MHz and 2.4 MHz. The experimental results showed that with the increase of laser power density, the phenomena of over saturation effect, saturated crosstalk effect, black line damage and black lines semi-cross damage appeared at different repetition rates. And the measured threshold and damage mechanism of CMOS were studied. Besides, based on the hydrodynamics theory, the laser-induced plasma density and temperature distribution of various materials (aluminum, copper and silicon) irradiated by the ps-laser were simulated, which provide a theoretical basis for the interaction of metals and semiconductors by the hundred picoseconds fiber laser
A high-energy quasi-continuous-wave (QCW) laser diode-pumped regenerative amplifier was demonstrated for using as a radiation source of laser-induced plasma. The seed source was an all-fiber amplifier, provided pulse width of 454 ps and single pulse energy of 7.7 nJ at a repetition rate of 24.17 MHz and a central wavelength of 1063.9 nm. The solid-state regenerative amplifier used a Nd:YAG crystal was side-pumped by QCW diode bars. With this system, high stability and high energy was generated at wavelength of 1064.1 nm, with pulse width of 392.1 ps and output average power was 4.04 W. The single pulse energy and peak power was 8.08 mJ and 20.6 MW, respectively. The M2 factor was about 1.48. The laser system will use as a picosecond radiation source for the following laser ablation and laser-induced plasma spectrum analysis. In the previous work, the process of laser-induced plasma was simulated by fluid dynamics. The temporal and spatial distribution of electron density and temperature was successfully simulated, corresponding the process of laser irradiation on target were recorded for set of materials (Si, Al, Cu). Finally, the mechanism and evolution process of the picosecond laser irradiation target were obtained.