Quantum cascade laser (QCL) emitting in the mid-wave infrared atmospheric windows (3 μm to 5 μm) will be of immediate use to several civilian applications, including airborne self-defense protection system and trace gas sensing and free space optical communications. At present, the mid-infrared laser sources mainly include solid-state optical parametric oscillation lasers, fiber lasers, and QCL. In these lasers, quantum cascade laser is the only one that can realize the conversion from electricity to light. Since its invention in 1994, with the deepening of scientific research, quantum cascade laser performance has been continuously improved, and the output laser power and beam quality of single transistor has been continuously improved. In this work, the output beam quality of QCL is analyzed. the evaluating method of the laser beam quality is analized in theory based on the Gaussian beam transmittion law. The output nearfiled and farfield of the single quantum cascade laser is measured in the experiment. The output divergence angle is calculated and the output beam quality is analized by using the M2 factor.
In high-power laser systems, the optics suffers from different degrees of damage due to high-power laser irradiation. Studying the laser-induced damage generation and growth law of the optics is greatly benefited by the ability to accurately predict how damage sites evolve with laser exposure. In this work, the laser-induced damage growth model in optics under high-power laser irradiation is described based on the Weibull distribution model. A parameter method for solving Weibull distribution model by using the least-square method is proposed. In addition, a Monte-Carlo analysis method is used to numerically simulate the growth law of laser-induced damage in optics based on the statistical theory. Furthermore, we have also predict the laser-induced damage growth trend for 20 shots in high-power laser systems.
In high-power solid-state laser, initiative pulse shaping can help improve the output laser’s performance. The evaluation
for output laser pulse is also incomplete. In this paper, we propose a method of initiative pulse shaping by using arbitrary
waveform generator (AWG), and establish a relatively complete evaluation system for the output pulses shape
simultaneously. It achieves the super-Gaussian pulse output with high SNR (signal-to-noise ratio). As a consequence, a
square laser pulse with pulse adjustable width ~5ns, rising time 197ps is obtained. The power imbalance of the output
square pulse is 3.72%. The similarity between the eight-order super-Gaussian pulse and the one we get from experiment