A novel differential velocity modulation laser spectroscopy

Experimental investigation of a novel differential velocity modulation laser spectroscopy is reported and demonstrated with the spectra of N2+A2IIm-X2∑g+ Meinel system. The S/N ratio excesses 500 : 1, about 60 times higher than that with the traditional non-differential technique.With this technique, we obtained the high-resolution electronic absorption spectra of A2II-X2∑+(1,0) vibration-al band of CS+ for the first time. It is confirmed that this technique will be a powerful method and receive wide application in studies of new molecular ions.