Comparison of femtosecond and nanosecond two-photon-absorption laser-induced fluorescence of krypton

摘要

Two-photon-absorption laser-induced fluorescence of Kr was explored using both nanosecond- and femtosecond-duration laser excitation sources. Fluorescence signals following two-photon excitation at two wavelengths (212.56 nm and 214.77 nm) were compared while varying laser pulse duration, energy, and excitation wavelength as well as pressure and Kr mole fraction in mixtures with nitrogen. Our findings show that stronger fluorescence was observed when the excitation wavelength was tuned to 212.56 nm, regardless of the excitation-pulse duration. Moreover, an approximate 100-fold signal enhancement from nanosecond excitation (similar to 3 mJ/pulse, 10 ns duration) was observed as compared to femtosecond excitation (similar to 6 mu J/pulse, 90 fs duration). (C) 2019 Optical Society of America