Graphene mode-locked Tm,Ho-codoped crystalline garnet laser producing 70-fs pulses near 2.1 mu m

Abstract

Bilayer graphene synthesized by chemical vapor deposition is successfully applied as a saturable absorber (SA) for the passive mode-locking of a Tm, Ho: CLNGG laser at 2093nm. Near transform-limited pulses as short as 70 fs, i.e., 10 optical cycles are produced at a 89MHz repetition rate with 69mW average output power. To the best of our knowledge, these are the shortest pulses ever reported from graphene-SA mode-locked Tm, or Ho-lasers in the 2 mu m spectral region, including bulk and fiber lasers.