High-order Raman sidebands generated from the near-infrared to ultraviolet region by four-wave Raman mixing of hydrogen using an ultrashort two-color pump beam

Abstract

A two-color pump beam consisting of a fundamental beam of a Ti:sapphire laser (35 fs, 802 nm) and a signal beam generated by optical parametric amplification (55 fs, 1203 nm) was utilized to generate multiple Raman sidebands by vibrational four-wave Raman mixing. The second harmonic emission (401 nm) was further employed as a seed beam for enhancing efficiency. Numerous sidebands emitting at 602, 481, 344, 301, 267, 241, 219, 200, and 185 nm were observed by irradiating the beam onto a screen coated with sodium salicylate. The spectral band width of these emission lines was capable of generating 0.9-fs optical pulses by Fourier synthesis.