Generation of ultrafast optical pulses via molecular modulation in ambient air

Abstract

We investigated the possibility of making ever-shorter optical pulses by using the nonlinearity of ambient air. We produced a broad spectrum consisting of mutually coherent optical sidebands via collinear Raman generation driven by two picosecond laser pulses that are Raman-resonant with molecular vibrations of nitrogen. We demonstrated the ability to adjust the sideband phases via dispersion control which we accomplished by changing the optical path length of the generated multi-color beam through a pair of tilted glass plates. The resultant measured phases suggest the generation of a 3-fs optical pulse train.