1 research outputs found
Graphene–Bi<sub>2</sub>Te<sub>3</sub> Heterostructure as Saturable Absorber for Short Pulse Generation
Rapid
progresses have been achieved in the photonic applications
of two-dimensional materials such as graphene, transition metal dichalcogenides,
and topological insulators. The strong light–matter interactions
and large optical nonlinearities in these atomically thin layered
materials make them promising saturable absorbers for pulsed laser
applications. Either Q-switching or mode-locking pulses with particular
output characteristics can be achieved by using different saturable
absorbers. However, it remains still very challenging to produce saturable
absorbers with tunable optical properties, in particular, carrier
dynamics, saturation intensity as well as modulation depth, to suit
for self-starting, high energy or ultrafast pulse laser generation.
Here we report a new type of saturable absorber which is a van der
Waals heterostructure consisting of graphene and Bi<sub>2</sub>Te<sub>3</sub>. The synergetic integration of these two materials by epitaxial
growth affords tunable optical properties, that is, both the photocarrier
dynamics and the nonlinear optical modulation are variable by tuning
the coverage of Bi<sub>2</sub>Te<sub>3</sub> on graphene. We further
fabricated graphene–Bi<sub>2</sub>Te<sub>3</sub> saturable
absorbers and incorporated them into a 1.5 μm fiber laser to
demonstrate both Q-switching and mode-locking pulse generation. This
work provides a new insight for tailoring two-dimensional heterostructures
so as to develop desired photonic applications