Advantages of non-collinear geometry in femtosecond travelling-wave parametric generation
Authors: Di Trapani P., Andreoni A., Banfi G.P., Danielius R., Foggi P., Monguzzi M., Piskarskas A., Solcia C., Sozzi C.
Autors Affiliation: Univ of Milano in Como, Como, Italy
Abstract: With ultrashort pulses, parametric gain is predicted to be larger in those directions that, beside phase matching, better satisfy group velocity (GV) matching. In the femtosecond regime one then expects the parametric superfluorescence pattern to be quite different than with longer pulses. We evidenced this peculiarity, and hence the role of GV, in a type II phase-matched BBO pumped by 200-fs pulses at 0.6 µm. We report the angle of peak parametric superfluorescence as a function of crystal orientation. We notice that the superfluorescence peak is neither collinear nor in directions related to walk-off. Significative parameters that account for the effect of GV on gain are presented.
KeyWords: Crystal orientation; Crystals; Geometry; Laser pulses; Laser tuning; Optical pumping; Second harmonic generation; Solid state lasers, Group velocity matching; Noncollinear geometry; Parametric gain; Phase matching; Sellmeier equations; Signal wavelength; Superfluorescence; Travelling wave generation, FluorescenceDOI: 10000000000