SPECTRAL ASYMMETRY BY GROUP-VELOCITY DISPERSION AND SELF-PHASE MODULATION IN HYBRIDLY MODE-LOCKED RH6G DYE-LASER WITH A PAIR OF BREWSTER PRISMS

In a hybridly mode-locked continuous-wave dye laser with a Rh6G satura ble gain and a 3,3'-diethyloxadicarbocyanine iodide saturable absorber , a pair of Brewster prisms were used to control the group velocity di spersion (GVD). Chirped spectra induced by GVD were dominant in the ca se of excess GVD compensations. The spectral asymmetry between excess positive and negative GVD compensation cases, was observed. Meanwhile, up-chirp due to the self-phase modulation was dominant in case of pro per GVD compensation. We also described the behaviour of linear chirpe d spectra and fitted the measured spectra with a linear chirp paramete r.