Spectral compression in CVBG
Ultrashort pulses are our domain. Sometimes, however, narrowband pulses - and therefore longer pulses are required (for example in Stimulated Raman Scattering spectroscopy). How can we create such a longer pulse? Our idea is as following: we divide a femtosecond pulse into two parts. We send both pulses into a volume Bragg gratin from the opposite sides. This way the two pulses acquire opposite phase. Finally we mix the two pulses (sum frequency generation) in a nonlinear crystal. The newly generated pulse is characterized by a narrow spectrum. See our article on this subject in the last Optics Letters.