Knowledge Bank

High resolution Raman spectra are obtained by CARS spectroscopy. The sources used are a pulsed ruby laser and a pulsed dye laser; the spectral width of these lasers are $2\times 10-3$ and $3\times 10-3cm-1$, so that the expected resolution is of the order of $4\times 10-3cm-1$. We shall show the spectrum of the $Q+$ branch of $\nu 3$ of $CH4$ for a gas under a pressure of 50 Torr.