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

Abstract

Large-area and highly crystalline transition metal dichalcogenides (TMDs) films possess superior saturable absorption compared to the TMDs nanosheet counterparts, which make them more suitable as excellent saturable absorbers (SA) for ultrafast laser technology. Thus far, the nonlinear optical properties of large-scale WSe 2 and its applications in ultrafast photonics have not yet been fully investigated. In this work, the saturable absorption of chemical vapor deposition (CVD) grown WSe 2 films with large-scale and high quality are studied and the use of WSe 2 films as a broadband SA for passively mode-locked fiber lasers at both 1.5 and 2 μm ranges is demonstrated. To enhance the light-material interaction, largearea WSe 2 film is tightly transferred onto the side wall of a microfiber to form a hybrid structure, which realizes strong evanescent wave interaction between light and WSe 2 film. The integrated microfiber-WSe 2 device shows a large modulation depth of 54.5%. Using the large-area WSe 2 as a mode-locker, stable soliton mode-locked pulse generation is achieved and the pulse durations of 477 fs (at 1.5 μm) and 1.18 ps (at 2.0 μm) are demonstrated, which suggests that the large-area and highly crystalline WSe 2 films afford an excellent broadband SA for ultrafast photonic applications. References and links 1. Q. H. Wang, K. Kalantar-Zadeh, A. Kis, J. N. Coleman, and M. S. Strano, "Electronics and optoelectronics of two-dimensional transition metal dichalcogenides," Nat. Nanotechnol. 7(11), 699-712 (2012). 2. K. F. Mak and J. Shan, "Photonics and optoelectronics of 2D semiconductor transition metal dichalcogenides," Nat. Photonics 10, 216-226 (2016 1974-1981 (2013). 2085-2087 (2012)

2D Layered Materials: Synthesis, Nonlinear Optical Properties, and Device Applications

“…Driven by these efforts, mode‐locked fiber lasers based on other layered TMDCs and their derivatives including MoSe 2 , MoTe 2 , WTe 2 , WSe 2 , MoSe 2 , SnS 2 , ReS 2 , In 2 Se 3 , InS, TiS 2 , PtS 2 , PtSe 2 , and HfS 2 , have also developed rapidly, as shown in Table . It can be seen that for these lasers, the minimum pulse width is 67 fs, maximum output power is 212 mW, and maximum repetition rate is 8.82 GHz .…”

Hafnium Sulfide Nanosheets for Ultrafast Photonic Device

“…Several approaches have been developed to achieve stable and reliable light‐matter interaction between light and nanomaterials, in order to construct compact and compatible fiber devices . The integration approach is so important that it directly influences the output performance of the devices.…”

“…The direct transmission–based devices can be easily fabricated by attaching 2D materials or polymer‐material composite to the end of a fiber, while such devices are usually suffered from a low thermal damage threshold . Evanescent field coupling–based devices that are formed by depositing 2D NSs or large‐scale film onto the side surface of a microfiber or side polished fiber, can overcome this issue, Currently, NSs deposition onto a fiber remains challenged, because it is not easy to control the density, length, and position of deposited material by the widely used optical deposition methods. In our experiment, a PCF assisted deposition method is demonstrate to precisely control the deposition, as schematically shown in Figure a.…”

“…Extensive efforts have been made in recent years to study the broadband nonlinear absorption and ultrafast carrier dynamics of low‐dimensional materials, which are particularly important in the field of ultrafast photonics . Since the successful demonstration of graphene‐based saturable absorber (SA) for ultrafast pulsed lasers, 2D layered materials including black phosphorus, topological insulators, and transition metal dichalcogenides (TMDs), have recently been extensively investigated in nonlinear optical devices for the generation of ultrafast pulses via passive mode‐locking operation . In particular, the recent advancements in the development of TMDs with unique electronic and optical attributes have explored many potential applications in electronics and photonics .…”

“…The TMDs with layered structure can be exfoliated into atomic‐thin layers, which advance the development of wider applications as high‐performance transistors, photodetectors and nonlinear optical devices owing to their widespread bandgaps from the visible to the near‐infrared region . Currently, nonlinear optical devices based on group VIB TMDs have been fully studied using as saturable absorbers (SA) for the successful generation of short pulses in broadband region . Despite the previous efforts, it is still possible to optimize the SA devices toward ultrafast photonics for the admired purposes of generating laser pulse with shorter pulse width and greater output power, which can be anticipated by exploring other members of TMDs.…”