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Van der Waals (vdW) materials have recently attracted significant interest in the context of orientation-dependent linear and nonlinear optical properties. Recently, arsenic trisulfide (As2S3) or orpiment is identified as a new vdW layered material having anisotropic vibrational and optomechanical responses due to the reduced in-plane crystal symmetry, but its nonlinear optical response is still not well understood yet. Herein, the anisotropic third-harmonic generation (THG) response of mechanically exfoliated As2S3thin flakes is reported. The polarization-dependent evolution of THG emission from butterfly-shaped pattern to four-lobe pattern is comprehensively explored. Moreover, the third-order nonlinear susceptibility of As2S3crystal is extracted by analyzing the thickness-dependent THG emission. We anticipate that the discussed results will not only update the existing understanding on the nonlinear light-matter interaction in anisotropic vdW materials, but also promote future applications in integrated photonic circuits, on-chip nonlinear signal processing, and polarization-sensitive optical devices.
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Anisotropic Third‐Harmonic Generation in Layered Germanium Selenide
Abstract Germanium selenide (GeSe) is a 2D layered material with an anisotropic crystal structure analogous to black phosphorus (BP). But unlike BP, GeSe is stable under ambient conditions and therefore provides more flexibility in building practical nanoscale devices. The in‐plane anisotropic vibrational, electrical, and optical properties of layered GeSe originating from the low symmetry of its crystal structure are being explored mostly for building polarization‐sensitive optoelectronic devices. However, the nonlinear optical properties of layered GeSe have not been investigated yet. Here, the anisotropic polarization‐dependent third‐harmonic generation (THG) from exfoliated thin GeSe flakes due to the low in‐plane lattice symmetry is reported. Furthermore, it is also shown that the intensity and polarization state of TH emission can be controlled by the polarization state of pump beam. Moreover, it is demonstrated that the crystal's symmetry axes can be rapidly determined by characterizing the intensity profile of TH emission upon the excitation from radially or azimuthally polarized vector beam. The results of this study pave the way for realizing anisotropic nonlinear optical devices such as multiplexers, signal processors, and other prototypes for future on‐chip photonic circuits and optical information processing.
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- PAR ID:
- 10457706
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Laser & Photonics Reviews
- Volume:
- 14
- Issue:
- 6
- ISSN:
- 1863-8880
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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