Two-brightness-amplifier imaging system for energetic-materials-combustion study

This paper discusses a laser monitor with two channels for acquiring images synchronized in time and its use for visualizing the surface of metal nanopowders during combustion. Each channel is an independent optical system based on a copper bromide vapor brightness amplifier and a high-speed camera that allows visualizing a specified area of the sample. Thus, the laser monitor allows real-time imaging of the same sample area with different spatial resolutions and simultaneously two areas of the sample. In comparison with the "master oscillator-power amplifier" system and a bistatic laser monitor in the proposed system, the radiation pulses of the brightness amplifiers are synchronized in such a way that the inversion in the active media is formed at different time intervals. Such a system makes it possible to register processes in one area of the sample in the mode of double frames with a time shift of 35 ns. As an additional option in the proposed system, it is possible to implement a laser illumination mode in which an additional camera is used with a narrow-band filter installed on it for the emission wavelength of brightness amplifiers, and the same radiation from the brightness amplifier is used as an illuminating light source. The proposed technique was used to visualize the combustion of aluminum nanopowders without additives in real time in the area of laser initiation with different spatial resolutions and nanoAl + microAl + microFe powder mixtures in the laser ignition area and the adjacent area of the sample simultaneously as the combustion wave propagates.