The nonlinear interaction of neutral krypton atoms with picosecond 193-nm radiation with intensities ≤1013 W/cm2 has been studied. Because of the relatively high intensity of the applied radiation field and the two-photon resonance of the 4p–6p transition, several competing nonlinear processes were observed that result in the generation of coherent radiation. Amplified spontaneous emission (ASE) from the two-photon-resonant level was observed in the IR frequency at ~2 μm. Additionally, a tunable IR wave, in the same frequency range, was generated by stimulated hyper-Raman scattering of the incident laser. The observed self-generated IR waves induced other nonlinear interactions, which resulted in the generation of extreme-ultraviolet (XUV) radiation in the same medium. Tunable XUV frequency was shown to be generated by four-wave sum mixing of the laser and the hyper-Raman wave. Vacuum-ultraviolet frequency was shown to be generated by four-wave oscillation, and other nontunable XUV frequencies resulted from anti-Stokes Raman scattering of the ASE IR waves.
© 1988 Optical Society of America
Original Manuscript: January 4, 1988
Manuscript Accepted: May 23, 1988
Published: November 1, 1988
M. Shahidi, T. S. Luk, and C. K. Rhodes, "Generation of infrared and extreme-ultraviolet radiation in krypton with picosecond irradiation at 193 nm," J. Opt. Soc. Am. B 5, 2386-2394 (1988)