Pulse compression without phase control and frequency detuning by high-order stimulated Raman scattering

Summary form only given. Optical pulse compression based on combination of spectral broadening by self-phase modulation and subsequent chirp compensation forms the physical basis for ultrashort pulse generation in the few-optical-cycle regime. The key element of this method is the necessary phase compensation technique with negative group delay dispersion. However, all methods for phase control are rather complex and cause difficulties for pulse compression below 5 fs. In the present talk we study an alternative method where an intense short pump pulse with duration smaller than the period of the molecular oscillations, /spl tau//sub pu/ < T/sub R/ = 2/spl pi///spl Omega/ (/spl Omega/ is the Stokes shift), effectively excites the Raman-active medium and a temporally delayed, weak probe pulse with duration /spl tau//sub pr/ < T/sub R/ is coherently scattered by the long-living Raman excitation.