GeAs2 Saturable Absorber for Ultrafast and Ultranarrow Photonic Applications. (4th February 2022)

• Record Type: Journal Article
• Authors: Liu, Shunxiang; Li, Gang; Zhu, Feng; Huang, Hongfu; Lu, Jinsheng; Qu, Junle; Li, Liang; Wen, Qiao
• Is Part Of: Advanced functional materials. Volume 32:Number 17(2022)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2022-02-04
• Subjects: GeAs 2 -- mode‐locking lasers -- saturable absorbers -- single‐frequency lasers; Materials -- Periodicals; Chemical vapor deposition -- Periodicals; 620.11
• DOI: 10.1002/adfm.202112252
• Languages: English
• ISSNs: 1616-301X

Abstract

Abstract: As a new IV–V group semiconductor, germanium‐diarsenide (GeAs2 ) compounds have attracted considerable attention due to their outstanding optical and electrical properties, thickness‐dependent bandgap, in‐plane anisotropy, and excellent optical absorption. However, the potential of GeAs2 in the field of ultrafast and ultranarrow fiber laser has not been studied. In this article, a high‐quality GeAs2 nanosheets saturable absorber (SA) is successfully prepared by liquid‐phase exfoliation. The nonlinear optical characteristics of GeAs2 nanosheets have been investigated based on a balanced twin‐detector measurement system. The modulation depth, nonsaturable loss, and saturation intensity are measured to be 5.2%, 24%, and 1.23 GW cm −2, respectively. GeAs2 has been successfully applied as an SA in an ultrafast and single‐frequency fiber laser. A stable mode‐locked laser pulses operation with a duration as short as 371 fs and a repetition rate of 8.19 MHz at a wavelength of 1560 nm is achieved. Moreover, ultranarrow fiber lasers with a high signal‐to‐noise ratio of 80 dB and a linewidth of ≈678 Hz are obtained. The findings validate that 2D GeAs2 can be used as an SA and has promising applications in ultrafast and ultranarrow photonics. Abstract : A high‐quality saturable absorber (SA) based on GeAs2 nanosheets is introduced. The saturation intensity and the modulation depth are measured to be 1.23 GW cm −2 and 5.2%, respectively. By incorporating this GeAs2 SA into fiber lasers, a high stable ultrafast fiber laser with a pulse duration of 371 fs and a single‐frequency fiber laser with a linewidth of ≈678 Hz are demonstrated, respectively.