Spin-to-orbital angular momentum conversion in harmonic generation driven by intense circularly polarized laser
Spin-to-orbital angular momentum conversion (STOC) is a very important fundamental phenomenon governed by the conservation of total angular momentum (TAM). In optics, this conversion is usually associated with the vortex light carrying the orbital angular momentum (OAM). In this paper we demonstrate...
| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
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IOP Publishing
2020-01-01
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| Series: | New Journal of Physics |
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| Online Access: | https://doi.org/10.1088/1367-2630/ab6873 |
| _version_ | 1797750335228346368 |
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| author | Shasha Li Xiaomei Zhang Weifeng Gong Zhigang Bu Baifei Shen |
| author_facet | Shasha Li Xiaomei Zhang Weifeng Gong Zhigang Bu Baifei Shen |
| author_sort | Shasha Li |
| collection | DOAJ |
| description | Spin-to-orbital angular momentum conversion (STOC) is a very important fundamental phenomenon governed by the conservation of total angular momentum (TAM). In optics, this conversion is usually associated with the vortex light carrying the orbital angular momentum (OAM). In this paper we demonstrate a new mechanism to achieve STOC via the interaction of an intense circularly polarized (CP) laser pulse with a solid density plasma target. We find that when a laser pulse with relativistic intensity is tightly focused, a longitudinal electric field is induced owing to the finite transverse size and profile of the laser field. Therefore, even for the normally incident CP laser, the induced longitudinal electric field can drive an oscillating vortex plasma surface to emit the vortex harmonics when the laser interacts with the plasma target. Based on simulations and theoretical analysis, we verify this harmonic generation mechanism and reveal the STOC process in the harmonic generation. It is shown that the spin angular momenta of multiple fundamental-frequency photons are converted to the OAM of a single harmonic photon because of the TAM conservation. We also discuss the dynamical symmetries in the harmonic generation process, which physically constrains the harmonic orders, as well as the angular momenta. In addition, if a vortex laser beam or a spiral phase plate is used, the OAM of the harmonic photon becomes more tunable and controllable. This study provides a deep insight into the nature of the spin–orbital interaction in optics. |
| first_indexed | 2024-03-12T16:31:16Z |
| format | Article |
| id | doaj.art-32e4b68aafae4149ba6c7228461418b7 |
| institution | Directory Open Access Journal |
| issn | 1367-2630 |
| language | English |
| last_indexed | 2024-03-12T16:31:16Z |
| publishDate | 2020-01-01 |
| publisher | IOP Publishing |
| record_format | Article |
| series | New Journal of Physics |
| spelling | doaj.art-32e4b68aafae4149ba6c7228461418b72023-08-08T15:27:36ZengIOP PublishingNew Journal of Physics1367-26302020-01-0122101305410.1088/1367-2630/ab6873Spin-to-orbital angular momentum conversion in harmonic generation driven by intense circularly polarized laserShasha Li0Xiaomei Zhang1Weifeng Gong2https://orcid.org/0000-0001-9626-6687Zhigang Bu3Baifei Shen4https://orcid.org/0000-0003-1021-6991State Key Laboratory of High Field Laser Physics, Shanghai Institute of Optic and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800, People’s Republic of China; University of Chinese Academy of Sciences , Beijing 100049, People’s Republic of ChinaState Key Laboratory of High Field Laser Physics, Shanghai Institute of Optic and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800, People’s Republic of ChinaState Key Laboratory of High Field Laser Physics, Shanghai Institute of Optic and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800, People’s Republic of China; University of Chinese Academy of Sciences , Beijing 100049, People’s Republic of ChinaState Key Laboratory of High Field Laser Physics, Shanghai Institute of Optic and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800, People’s Republic of ChinaState Key Laboratory of High Field Laser Physics, Shanghai Institute of Optic and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800, People’s Republic of China; Department of Physics, Shanghai Normal University , Shanghai, 200234, People’s Republic of ChinaSpin-to-orbital angular momentum conversion (STOC) is a very important fundamental phenomenon governed by the conservation of total angular momentum (TAM). In optics, this conversion is usually associated with the vortex light carrying the orbital angular momentum (OAM). In this paper we demonstrate a new mechanism to achieve STOC via the interaction of an intense circularly polarized (CP) laser pulse with a solid density plasma target. We find that when a laser pulse with relativistic intensity is tightly focused, a longitudinal electric field is induced owing to the finite transverse size and profile of the laser field. Therefore, even for the normally incident CP laser, the induced longitudinal electric field can drive an oscillating vortex plasma surface to emit the vortex harmonics when the laser interacts with the plasma target. Based on simulations and theoretical analysis, we verify this harmonic generation mechanism and reveal the STOC process in the harmonic generation. It is shown that the spin angular momenta of multiple fundamental-frequency photons are converted to the OAM of a single harmonic photon because of the TAM conservation. We also discuss the dynamical symmetries in the harmonic generation process, which physically constrains the harmonic orders, as well as the angular momenta. In addition, if a vortex laser beam or a spiral phase plate is used, the OAM of the harmonic photon becomes more tunable and controllable. This study provides a deep insight into the nature of the spin–orbital interaction in optics.https://doi.org/10.1088/1367-2630/ab6873angular momentum conversionharmonic generationlaser-plasma interaction |
| spellingShingle | Shasha Li Xiaomei Zhang Weifeng Gong Zhigang Bu Baifei Shen Spin-to-orbital angular momentum conversion in harmonic generation driven by intense circularly polarized laser New Journal of Physics angular momentum conversion harmonic generation laser-plasma interaction |
| title | Spin-to-orbital angular momentum conversion in harmonic generation driven by intense circularly polarized laser |
| title_full | Spin-to-orbital angular momentum conversion in harmonic generation driven by intense circularly polarized laser |
| title_fullStr | Spin-to-orbital angular momentum conversion in harmonic generation driven by intense circularly polarized laser |
| title_full_unstemmed | Spin-to-orbital angular momentum conversion in harmonic generation driven by intense circularly polarized laser |
| title_short | Spin-to-orbital angular momentum conversion in harmonic generation driven by intense circularly polarized laser |
| title_sort | spin to orbital angular momentum conversion in harmonic generation driven by intense circularly polarized laser |
| topic | angular momentum conversion harmonic generation laser-plasma interaction |
| url | https://doi.org/10.1088/1367-2630/ab6873 |
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