Laser Monitor with Independent Illumination from Capacitive-Discharge-Pumped CuBr Laser for Metal Nanopowder Combustion Study

This paper discusses a laser monitor with independent illumination (bistatic) for visualizing the surface of metal nanopowders during combustion. The laser monitor consists of a brightness amplifier based on copper bromide vapors with conventional pumping, which forms an amplified image of the surface of the observation object, a high-speed camera, and a capacitive-discharge-pumped copper bromide vapor laser that illuminates the surface of the object at the amplification wavelength. The operation of the brightness amplifier and the illuminating laser is synchronized with high accuracy due to the use of a high-voltage double-pulse generator based on one pulse converter, and the coordinated triggering of two thyratrons through adjustable delay lines. The optimal delays between the radiation pulses of the brightness amplifier and the illuminating laser, at which the brightest and most contrasting image is achieved, have been determined. Using the proposed technique, the surface of an aluminum nanopowder and a nanoAl+nanoFe mixture was visualized during combustion.