Spectral Selection System of Narrow Band Radiation of the Excimer KrF Laser

The work describes the system for spectral filtering of probing radiation for studying the dynamics of photofragments during double-pulse excitation of molecules by the LF/LIF method. The parameters of the special narrow-band excimer KrF laser used to excite laser-induced fluorescence of PO molecules are presented. Using the AvaSpec-3648 fiber-optic spectrometer installed in the transmission path of the KrF excimer laser radiation, an analysis of the spectral composition of the output laser radiation was carried out. Using the ZEMAX CAD system, the optical design of the system for spectral filtering of KrF laser probing radiation was calculated. Theoretical results of calculating the position of the probe narrow-band radiation beam at the edge of the gain of the KrF laser with a wavelength of 247.8 nm and the broadband spontaneous radiation of the KrF laser in the wavelength range 248.2–248.5 nm are presented. Experimental results for assessing the effectiveness of the spectral filtering unit for probing radiation based on the spatial separation of the spectral components contained in the output radiation in a controlled region of space are presented.