Determination of the Dicke narrowing in gaseous hydrogen by direct measurement of the dephasing time

A system was developed for transient coherent active Raman spectroscopy of molecular gases in which a picosecond optical parametric oscillator was used. This method was used to measure the dephasing time of molecular parametric oscillator vibrations and thus find the Dicke narrowing of the Q₁ line of hydrogen and to demonstrate that a high spectral resolution was possible.