This paper reports the simultaneous output of 358.7nm and 420.3nm laser generated by two-photon excitation (52 S1/2→62 D5/2, TPE) and four-wave mixing effect (FWM) in rubidium system for the first time. Unlike some fluorescent signals, this four-wave mixing beam has a high monochromaticity and extreme directivity and can be used as a laser source. In this study, we also measured the fluorescence lines in the range of 300-820 nm under 52 S1/2→62 D5/2 TPE, and studied other transitions that may occur. The experimental results show that the blue-violet laser produced by this alkali metal rubidium four-wave mixing can provide a new laser source for underwater laser communication, display technology, fluorescence excitation, Raman spectroscopy, marine resource detection, laser biomedicine, lithography, high density information storage and other fields.
After the multiphoton ionization of sodium-argon mixture, time-resolved atomic emission spectrum is used to experimentally study the unusual phenomenon of the obviously different broadening between Na D1 and D2 lines spectra. The primary reason for the unusual broadening of Na D2 line is that the spectral line of Ar I 588.9 nm overlays with Na D2 line (589.0 nm) after ionization, and the serious self-absorption on Na D2 line is the secondary reason. Although there is difference of population between 32P3/2 and 32P1/2 states, the experiment result demonstrates that the difference between Na D lines in radiation channel will not affect the broadening of spectral profile.
The kinetic behaviors of 6p[1/2]0, 6p[3/2]2 ,and 6p[5/2]2 were examined under the ultrahigh pumped power. These processes were detected by the way of time-resolved fluorescence and ASE spectra. A theory of energy-pooling is presented under the focused condition. There are three types of energy-pooling processes. The first type is energy-pooling ionization. The obvious ionization can be observed whenever the laser prepared state is the 6p[1/2]0, 6p[3/2]2, or 6p[5/2]2 state. The second type is energy-pooling with big energy difference. The energy-pooling collision between the two 6p[1/2]0 atoms can produce one 5d[3/2]1 atom and one 6s’[1/2]0 atom when the prepared state is 6p[1/2]0. The third type is energy-pooling with small energy difference. The way of generation of five secondary 6p states is energy-pooling instead of collision relaxation.