Broadband Few‐Layer MoS₂ Saturable Absorbers

Abstract

The bandgaps of monolayer and bulk molybdenum sulfide (MoS2 ) result in that they are far from suitable for application as a saturable absorption device. In this paper, the operation of a broadband MoS2 saturable absorber is demonstrated by the introduction of suitable defects. It is believed that the results provide some inspiration in the investigation of two-dimensional optoelectronic materials.

Large-area highly crystalline WSe_2 atomic layers for ultrafast pulsed lasers

“…For example, recent reports have demonstrated the broadband saturable absorption of MoS 2 due to the introduction of both Mo and S defects [11,37]. In our work, the W defects of WSe 2 films identified from the EDS spectrum and the edges of small WSe 2 triangles observed from the AFM image may make significant contribution to the broadband saturable absorption, which is analogous to that of previously reported MoS 2 [11,37,38]. …”

“…The mechanism of saturable absorption at 0.8 eV and 0.67 eV originates from the subbandgap absorption due to the edges or defects in the small triangular shapes of WSe 2 , which also has been experimentally and theoretically demonstrated in other TMDs nanoflakes [37,38]. For example, recent reports have demonstrated the broadband saturable absorption of MoS 2 due to the introduction of both Mo and S defects [11,37]. In our work, the W defects of WSe 2 films identified from the EDS spectrum and the edges of small WSe 2 triangles observed from the AFM image may make significant contribution to the broadband saturable absorption, which is analogous to that of previously reported MoS 2 [11,37,38].…”

“…Recent reports have demonstrated that the energy band structures of the semiconducting TMDs show a unique transition from indirect to direct band gap as the thickness is reduced to monolayer [5][6][7]. These monolayer TMDs with direct band gap can offer exciting opportunities for potential applications in both electronic and optoelectronic devices [4, [8][9][10][11][12][13][14][15][16][17]. Among all TMD materials, WSe 2 has recently received huge interest due to their distinctive electro-optical properties and remarkable electronic characteristics [18][19][20][21][22][23][24].…”

Simulations and experiments showing the origin of multiwavelength mode locking in femtosecond, Yb-fiber lasers

“…As well as traditional mechanisms based on nonlinear polarisation evolution (NPE) arising from the Kerr effect in the fibers [2] various external materials have been harnessed to create the required fast switches in such cavities, such as semiconductor saturable absorber mirrors (SESAMs [3,4] or, more recently, saturable absorbers based on two dimensional materials suchg as MoS 2 and graphene [5][6][7][8][9][10]). While some recent research has focussed on polarisation-maintaining (PM) fiber cavities [11], a large number of cavities have continued to use non-PM fibers and with NPE as a fast saturable absorber, either in combination with a SESAM or, as here, acting in tandem with a spectral filter.…”

Generation of passively Q-switched fiber laser at 1 μm by using MoSSe as a saturable absorber

“…TMDs encompass various transition metal compounds, such as molybdenum sulfide (MoS 2 ) [16][17][18] , molybdenum diselenide (MoSe 2 ) [19] , tungsten disulfide (WS 2 ) [20][21][22] , and tungsten diselenide (WSe 2 ) [23] , and have been successfully demonstrated in Q-switched fiber laser operations. TMDs in particular exhibit layer-dependent optical properties and, at near-infrared wavelengths, have the ability to alternate their bandgap between indirect and direct, making them highly desirable as optical materials [24] . Furthermore, TMDs have high non-linearity, ultrafast carrier dynamics, great photoluminescence, and strong absorption, making them suitable for a variety of photonic applications [25,26] .…”