Graphene mode-locked femtosecond Cr2+:ZnS laser with ~300 nm tuning range.
Graphene has proved to be an excellent broadband saturable absorber for mode-locked operation of ultrafast lasers. However, for the mid-infrared (mid-IR) range where broadly tunable sources are in great needs, graphene-based broadly tunable ultrafast mid-IR lasers have not been demonstrated so far. Here, we report on passive mode-locking of a mid-IR Cr:ZnS laser by utilizing a transmission-type monolayer graphene saturable absorber and broad spectral tunability between 2120 nm and 2408 nm, which is the broadest tuning bandwidth ever reported for graphene mode-locked mid-IR solid-state lasers. The recovery time of the saturable absorber is measured to be ~2.4 ps by pump-probe technique at a wavelength of 2350 nm. Stably mode-locked Cr:ZnS laser delivers Fourier transform-limited 220-fs pulses with a pulse energy of up to 7.8 nJ.
Won Bae
WB
Cho
Sun Young
SY
Choi
Chunhui
C
Zhu
Mi Hye
MH
Kim
Jun Wan
JW
Kim
Jin Sun
JS
Kim
Hyung Ju
HJ
Park
Dong Ho
DH
Shin
Moon Youn
MY
Jung
Fengqiu
F
Wang
Fabian
F
Rotermund