Attosecond All-Optical Retrieval of Valley Polarization via Circular Dichroism in Transient Absorption
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arXiv
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| Main Authors: | , , , , , , , |
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| Format: | Preprint |
| Published: |
2024
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| _version_ | 1866913979488534528 |
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| author | Li, Wenqing Zhu, Xiaosong Lan, Pengfei Wang, Kai He, Wanzhu Hübener, Hannes De Giovannini, Umberto Lu, Peixiang |
| author_facet | Li, Wenqing Zhu, Xiaosong Lan, Pengfei Wang, Kai He, Wanzhu Hübener, Hannes De Giovannini, Umberto Lu, Peixiang |
| contents | We propose a scheme for retrieving the ultrafast valley polarization (VP) dynamics in two-dimensional hexagonal materials via attosecond circular dichroism (CD) transient absorption spectroscopy. This approach builds on the CD transition between the first and higher conduction bands induced by the circularly polarized probe pulses. The population imbalance at nonequivalent valleys in the first conduction band is proportionally mapped onto the difference in absorption coefficients of two probe pulses with opposite helicities, supporting an unprecedented quantitative retrieval of the corresponding VP dynamics with subfemtosecond time resolution. We theoretically demonstrate the scheme for h-BN and MoS2 through ab initio calculations, achieving an accurate retrieval of the VP dynamics, particularly the transient VP switching processes, with a time resolution of 250 as. |
| format | Preprint |
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arxiv_https___arxiv_org_abs_2412_19612 |
| institution | arXiv |
| publishDate | 2024 |
| record_format | arxiv |
| spellingShingle | Attosecond All-Optical Retrieval of Valley Polarization via Circular Dichroism in Transient Absorption Li, Wenqing Zhu, Xiaosong Lan, Pengfei Wang, Kai He, Wanzhu Hübener, Hannes De Giovannini, Umberto Lu, Peixiang Optics We propose a scheme for retrieving the ultrafast valley polarization (VP) dynamics in two-dimensional hexagonal materials via attosecond circular dichroism (CD) transient absorption spectroscopy. This approach builds on the CD transition between the first and higher conduction bands induced by the circularly polarized probe pulses. The population imbalance at nonequivalent valleys in the first conduction band is proportionally mapped onto the difference in absorption coefficients of two probe pulses with opposite helicities, supporting an unprecedented quantitative retrieval of the corresponding VP dynamics with subfemtosecond time resolution. We theoretically demonstrate the scheme for h-BN and MoS2 through ab initio calculations, achieving an accurate retrieval of the VP dynamics, particularly the transient VP switching processes, with a time resolution of 250 as. |
| title | Attosecond All-Optical Retrieval of Valley Polarization via Circular Dichroism in Transient Absorption |
| topic | Optics |
| url | https://arxiv.org/abs/2412.19612 |