Vibrational molecular modulation in hydrogen

Detailed numerical modeling of using the vibrational coherence of H₂ for molecular modulation is presented. The focus of the calculation is on a strongly driven system aimed at producing many sidebands in the presence of Doppler broadening and the effects of collisions at room temperature. It is shown that Dicke narrowing that reduces the Doppler width plays a critical role in high order sideband generation in room temperature H₂. In addition, the calculation shows that generation of many sidebands favors the phased state as has been reported in all gas phase experiments and is primarily a consequence of the Stark shifts that result from the applied high intensities. The influence of self-focusing in the gas medium that has been conjectured in previous studies is only secondary. The numerical results agree with experimental data obtained in our laboratory, where we have succeeded in generating collinearly propagating Raman sidebands with wavelengths that range from 22160.3em0exnm in the infrared to 1330.3em0exnm in the vacuum ultraviolet. The frequencies covered by these sidebands span over four octaves for a total of more than 700.2em0ex6000.3em0excm^-1 in the optical region of the spectrum.