The generation of UV third-harmonic radiation by a focused laser beam in a positively dispersive gaseous medium is investigated. The nonlinear gas is confined to a focal half-space by using a differentially pumped gas cell. The resulting density gradient along the beam axis is shown to provide an efficient frequency conversion in spectral regions of positive dispersion. Experimental results obtained in argon at λ ∼ 197 nm, which compare favorably with theory, are presented.
© 1994 Optical Society of America
Original Manuscript: October 19, 1992
Revised Manuscript: June 14, 1993
Published: March 20, 1994
R. Eramo and M. Matera, "Third-harmonic generation in positively dispersive gases with a novel cell," Appl. Opt. 33, 1691-1696 (1994)