Transition of pulsed operation from Q-switching to continuous-wave mode-locking in a Yb:KLuW waveguide laser

Identifier:  imarina:6494585

Handle: https://hdl.handle.net/20.500.11797/imarina6494585

Authors:  Bae, Ji Eun; Mateos, Xavier; Aguilo, Magdalena; Diaz, Francesc; Vazquez de Aldana, Javier Rodriguez; Romero, Carolina; Lee, Hansuek; Rotermund, Fabian

Abstract:
© 2020 Optical Society of America. We report on the diverse pulsed operation regimes of a femtosecond-laser-written Yb:KLuW channel waveguide laser emitting near 1040 nm. By the precise position tuning of a carbon-nanotube-coated saturable absorber (SA) mirror, the transition of the pulsed operation from Q-switching, Q-switched mode-locking and finally sub-GHz continuous-wave mode-locking are obtained based on the interplay of dispersion and mode area control. The Q-switched pulses exhibit typical fast SA Q-switched pulse characteristics depending on absorbed pump powers. In the Q-switched mode-locking, amplitude modulations of the mode-locked pulses on the Q-switched envelope are observed. The radio-frequency spectrum represents the coexistence of Q-switching and mode-locking signals. In the purely mode-locked operation, the waveguide laser generates 2.05-ps pulses at 0.5 GHz.