Abstract
Two-dimensional (2D) layered transition metal dichalcogenides (TMDs) have attracted significant interest in various optoelectronic applications due to their excellent nonlinear optical properties. One of the most important applications of TMDs is to be employed as an extraordinary optical modulation material (e.g., the saturable absorber (SA)) in ultrafast photonics. The main challenge arises while embedding TMDs into fiber laser systems to generate ultrafast pulse trains and thus constraints their practical applications. Herein, few-layered WS2 with a large-area was directly transferred on the facet of the pigtail and acted as a SA for erbium-doped fiber laser (EDFL) systems. In our study, WS2 SA exhibited remarkable nonlinear optical properties (e.g., modulation depth of 15.1% and saturable intensity of 157.6 MW cm-2) and was used for ultrafast pulse generation. The soliton pulses with remarkable performances (e.g., ultrashort pulse duration of 1.49 ps, high stability of 71.8 dB, and large pulse average output power of 62.5 mW) could be obtained in a telecommunication band. To the best of our knowledge, the average output power of the mode-locked pulse trains is the highest by employing TMD materials in fiber laser systems. These results indicate that atomically large-area WS2 could be used as excellent optical modulation materials in ultrafast photonics.
Highlights
IntroductionAs a representative of the semiconducting transition metal dichalcogenides (TMDs) family, WS2 has unique properties such as high carrier dynamics (∼140 cm[2] V−1 s−1), high third-order nonlinear susceptibility (Im χ3 ∼ 10−8), and broadband light absorption.[10,11,12] the theoretical models predict that WS2 has the highest carrier mobility among the semiconducting TMDs due to a better ballistic performance.[13]
To the best of our knowledge, the average output power of the mode-locked pulse trains is the highest by employing transition metal dichalcogenides (TMDs) materials in fiber laser systems. These results indicate that atomically large-area WS2 could be used as excellent optical modulation materials in ultrafast photonics
According to the two-level model (eqn (1)) for the interpretation of the saturable absorption property of TMDs, where αsat is the modulation depth (MD), αnon-sat is the non-saturable loss, and Isat is the saturable intensity, the value of MD for our WS2 SA might be larger than the measured value, which is limited by the measured range of our equipment.[28,29,30]
Summary
As a representative of the semiconducting TMD family, WS2 has unique properties such as high carrier dynamics (∼140 cm[2] V−1 s−1), high third-order nonlinear susceptibility (Im χ3 ∼ 10−8), and broadband light absorption.[10,11,12] the theoretical models predict that WS2 has the highest carrier mobility among the semiconducting TMDs due to a better ballistic performance.[13]. Few-layer WS2 was obtained via LPE or ME methods resulting in an uncontrollable size and random thickness, which limits the performances of WS2 once employed in a fiber laser system These disadvantages result in a more complicated process to prepare saturable absorbers based on few-layer WS2. Enormous progress on the growth of WS2 by a chemical vapour deposition (CVD) method has significantly decreased the complexity to prepare few-layered WS2 with a large-area and offered a more efficient approach to study the optoelectronic properties of WS2.20–23 Recent reports of the SAs based on atomic-layer WS2 exhibited the potential of this 2D semiconducting material and passive mode locking operation could be achieved, incorporated with few-layered WS2 nanosheets.[24] the saturable absorption mechanism of few-layered WS2 with a large-area has not yet been demonstrated and understood. In our experiment that used a few-layered WS2 SA, the soliton mode-locked pulses could be attained in an EDFL system with excellent laser performances such as a pulse duration of 1.49 ps, signal to noise ratio (SNR) of 71.8 dB, and an average output pulse power of 62.5 mW, showing its feasibility for use in ultrafast pulsed fiber lasers
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
