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Ultrafast beam pattern modulation by superposition of chirped optical vortex pulses
| Title: | Ultrafast beam pattern modulation by superposition of chirped optical vortex pulses |
| Authors: | Honda, Asami Browse this author | | Yamane, Keisaku Browse this author →KAKEN DB | | Iwasa, Kohei Browse this author | | Oka, Kazuhiko Browse this author →KAKEN DB | | Toda, Yasunori Browse this author →KAKEN DB | | Morita, Ryuji Browse this author →KAKEN DB |
| Issue Date: | 2-Sep-2022 |
| Publisher: | Nature Portfolio |
| Journal Title: | Scientific reports |
| Volume: | 12 |
| Start Page: | 14991 |
| Publisher DOI: | 10.1038/s41598-022-18145-4 |
| Abstract: | As an extension of pulse shaping techniques using the space-time coupling of ultrashort pulses or chirped pulses, we demonstrated the ultrafast beam pattern modulation by the superposition of chirped optical vortex pulses with orthogonal spatial modes. The stable and robust modulations with a modulation frequency of sub-THz were carried out by using the precise phase control technique of the constituent pulses in both the spatial and time/frequency domains. The performed modulations were ultrafast ring-shaped optical lattice modulation with 2, 4 and 6 petals, and beam pattern modulations in the radial direction. The simple linear fringe modulation was also demonstrated with chirped spatially Gaussian pulses. While the input pulse energy of the pulses to be modulated was 360 mu J, the output pulse energy of the modulated pulses was 115 mu J with the conversion efficiency of similar to 32%. Demonstrating the superposition of orthogonal spatial modes in several ways, this ultrafast beam pattern modulation technique with high intensity can be applicable to the spatially coherent excitation of quasi-particles or collective excitation of charge and spin with dynamic degrees of freedom. Furthermore, we analyzed the Poynting vector and OAM of the composed chirped OV pulses. Although the ring-shaped optical lattice composed of OV pulse with topological charges of +/- l is rotated in a sub-THz frequency, the net orbital angular momentum (OAM) averaged over one optical period is found to be negligible. Hence, it is necessary to require careful attention to the application of the OAM transfer interaction with matter by employing such rotating ring-shaped optical lattices. |
| Type: | article |
| URI: | http://hdl.handle.net/2115/86918 |
| Appears in Collections: | 工学院・工学研究院 (Graduate School of Engineering / Faculty of Engineering) > 雑誌発表論文等 (Peer-reviewed Journal Articles, etc)
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