Open AccessPolarization-dependent nonlinear optical response in GeSe<sub>2</sub>
Author(s) -
Hao Ouyang,
Siyang Hu,
Shen Man-Ling,
Chen-Xi Zhang,
Xin Cheng,
Tian Jiang
Publication year - 2020
Publication title -
wuli xuebao
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.199
H-Index - 47
ISSN - 1000-3290
DOI - 10.7498/aps.69.20200443
Subject(s) - excited state , materials science , polarization (electrochemistry) , excitation , absorption edge , wavelength , optics , absorption (acoustics) , absorption band , absorption spectroscopy , atomic physics , band gap , optoelectronics , physics , chemistry , quantum mechanics
Germanium diselenide (GeSe 2 ), a layered IV-VI semiconductor, has an in-plane anisotropic structure and a wide band gap, exhibiting unique optical, electrical, and thermal properties. In this paper, polarization axis Raman spectrum and linear absorption spectrum are used to characterize the crystal axis orientation and energy band characteristics of GeSe 2 flake, respectively. Based on the results, a micro-domain I scan system is used to study the optical nonlinear absorption mechanism of GeSe 2 near the resonance band. The results show that the nonlinear absorption mechanism in GeSe 2 is a superposition of saturation absorption and excited state absorption, and is strongly dependent on the polarization and wavelength of incident light. Under near-resonance excitation (450 nm), the excited state absorption is more greatly dependent on polarization. With different polarizations of incident light, the modulation depth can be changed from 4.6% to 9.9%; for non-resonant excitation (400 nm), the modulation depth only changes from 7.0% to 9.7%. At the same time, compared with saturation absorption, the polarization-dependent excited state absorption is greatly affected by the distance away from the resonance excitation wavelength.