Abstract

The generation of frequency upshifted, pressure-tunable third-harmonic pulses during ultrafast ionization of subatmospheric noble gases at peak intensity 10¹⁶ W/cm² is reported. Pressure tuning of the power spectrum centroid over the range 10⁻⁵ ≲ Δω/ω ≲ 10⁻¹, corresponding to a pressure range of 0.1 ≲ p ≲ 700 Torr, is demonstrated. We also demonstrate that the blue-shifted portions of both the 3ω and the ω pulses are preferentially self-guided in a limited pressure range (10 ≲ p ≲ 500 Torr), which is key to separating the pressure-tunable component of the harmonic from nontunable harmonic generated by means of atomic nonlinearities.

© 1996 Optical Society of America

Laser ionization of noble gases by Coulomb-barrier suppression

S. Augst, D. D. Meyerhofer, D. Strickland, and S. L. Chin
J. Opt. Soc. Am. B 8(4) 858-867 (1991)

Spectral, temporal, and spatial characteristics of plasma-induced spectral blue shifting and its application to femtosecond pulse measurement

S. P. Le Blanc and R. Sauerbrey
J. Opt. Soc. Am. B 13(1) 72-88 (1996)

Spectral shifting by optical and collisional ionization of an intense laser pulse in dense noble gases

M. Ciarrocca, J. P. Marangos, D. D. Burgess, and K. Burnett
J. Opt. Soc. Am. B 13(5) 794-804 (1996)

Effect of plasma-core-induced self-guiding on phase matching of high-order harmonic generation in gases

Balázs Major, Katalin Kovács, Valer Tosa, Piotr Rudawski, Anne L’Huillier, and Katalin Varjú
J. Opt. Soc. Am. B 36(6) 1594-1601 (2019)

Third-harmonic generation at atmospheric pressure in methane by use of intense femtosecond pulses in the tight-focusing limit

G. Marcus, A. Zigler, and Z. Henis
J. Opt. Soc. Am. B 16(5) 792-800 (1999)