Dichroic Photoelasticity in Black Phosphorus Revealed by Ultrafast Coherent Phonon Dynamics
| Autor: | Fanjie Wang, Zixuan Lu, Hao Zhang, Anqi Hu, Hugen Yan, Simin Wu, Zhengzong Sun, Minbiao Ji, Xianchong Miao |
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| Rok vydání: | 2021 |
| Předmět: |
Photoelasticity
Materials science Condensed matter physics Phonon Physics::Optics 02 engineering and technology 021001 nanoscience & nanotechnology Polarization (waves) 01 natural sciences Condensed Matter::Materials Science Zigzag 0103 physical sciences Femtosecond Ultrafast laser spectroscopy General Materials Science Physical and Theoretical Chemistry 010306 general physics 0210 nano-technology Anisotropy Refractive index |
| Zdroj: | The Journal of Physical Chemistry Letters. 12:5871-5878 |
| ISSN: | 1948-7185 |
| DOI: | 10.1021/acs.jpclett.1c01463 |
| Popis: | Coherent longitudinal lattice vibrations of black phosphorus provide unique access to the out-of-plane strain coupled in-plane optical properties. In this work, polarization-resolved femtosecond transient absorption microscopy is applied to study the anisotropic coherent phonon responses. Multiorder phonon harmonics were observed with thickness dependence well explained by the linear chain model, allowing rapid optical mapping of phonon frequency distributions. More interestingly, exotic coherent phonon oscillations occourred with a π-phase jump between the armchair and zigzag polarizations, which reveals opposite signs of photoelasticity under the longitudinal strain. Specifically, compressive strain reduces the imaginary refractive index in the armchair polarization but increases the real refractive index in the zigzag polarization, as confirmed by the ab initio calculations and thin film model. These fundamental properties of black phosphorus hold potential for applications in ultrafast and polarization-sensitive photoacoustic/photoelastic modulators. |
| Databáze: | OpenAIRE |
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