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| Main Authors: | , , , , , , , , , , , |
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| Format: | Preprint |
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2025
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| Subjects: | |
| Online Access: | https://arxiv.org/abs/2509.08663 |
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| _version_ | 1866909780332773376 |
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| author | Zhang, Xuefeng Nie, Zhongquan Zou, Jinhai Zhang, Hanke Wang, Xiaobin Wu, Jian Zhang, Yuqiu Leng, Jinyong Li, Guohui Tian, Yue Jia, Baohua Zhou, Pu |
| author_facet | Zhang, Xuefeng Nie, Zhongquan Zou, Jinhai Zhang, Hanke Wang, Xiaobin Wu, Jian Zhang, Yuqiu Leng, Jinyong Li, Guohui Tian, Yue Jia, Baohua Zhou, Pu |
| contents | Ultrafast all-optical switching (AOS) is pivotal for advancing integrated photonic devices, from high-speed photonic information processing to next generation all-optical computing and communication networks. However, conventional nonlinear materials suffer from sluggish response time, high power threshold, weak and narrow-bandwidth optical nonlinearities, critically limiting their viability. Here, we report a heteroatom engineering strategy to overcome these limitations by designing zero-dimensional nitrogen-doped carbon quantum dots (N-CQDs) with nonlinear optical performance far exceeding the state-of-the-art. Leveraging spatial self-phase modulation (SSPM) and ultrafast pump-probe technique, we first demonstrate an all-in-one AOS platform, where femtosecond laser pulses serve dual roles as control and signal beams. The AOS simultaneously realizes ultrafast response time (520 fs), ultralow threshold energy (2.2 Wcm-2), and giant nonlinear refraction indexes (10-5 cm2/W) in the wide spectral range (400-1064 nm), yielding performance surpassing state-of-the-art nonlinear carbon materials (i.e. carbon nanotube) by orders of magnitude. Spectroscopic and bandgap analyses attribute these exotic performances to enhanced n-pi interaction enabled by nitrogen doping, which amplifies nonlinear polarization dynamics. Crucially, ultrafast fluorescence spectroscopy reveals a large two-photon absorption cross-section of the N-CQDs, challenging the conventional cognition that broadband SSPM necessitates single-photon excitation. This discovery unveils a multi-channel AOS rooted in synergistic single-photon and two-photon processes.. This work demonstrates a new paradigm for achieving ultrafast, broadband, and energy-efficient AOS by heteroatom doping engineering. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2509_08663 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | Femtosecond low-threshold all-optical switching enabled by giant broadband optical nonlinearity from heteroatom doping Zhang, Xuefeng Nie, Zhongquan Zou, Jinhai Zhang, Hanke Wang, Xiaobin Wu, Jian Zhang, Yuqiu Leng, Jinyong Li, Guohui Tian, Yue Jia, Baohua Zhou, Pu Optics Ultrafast all-optical switching (AOS) is pivotal for advancing integrated photonic devices, from high-speed photonic information processing to next generation all-optical computing and communication networks. However, conventional nonlinear materials suffer from sluggish response time, high power threshold, weak and narrow-bandwidth optical nonlinearities, critically limiting their viability. Here, we report a heteroatom engineering strategy to overcome these limitations by designing zero-dimensional nitrogen-doped carbon quantum dots (N-CQDs) with nonlinear optical performance far exceeding the state-of-the-art. Leveraging spatial self-phase modulation (SSPM) and ultrafast pump-probe technique, we first demonstrate an all-in-one AOS platform, where femtosecond laser pulses serve dual roles as control and signal beams. The AOS simultaneously realizes ultrafast response time (520 fs), ultralow threshold energy (2.2 Wcm-2), and giant nonlinear refraction indexes (10-5 cm2/W) in the wide spectral range (400-1064 nm), yielding performance surpassing state-of-the-art nonlinear carbon materials (i.e. carbon nanotube) by orders of magnitude. Spectroscopic and bandgap analyses attribute these exotic performances to enhanced n-pi interaction enabled by nitrogen doping, which amplifies nonlinear polarization dynamics. Crucially, ultrafast fluorescence spectroscopy reveals a large two-photon absorption cross-section of the N-CQDs, challenging the conventional cognition that broadband SSPM necessitates single-photon excitation. This discovery unveils a multi-channel AOS rooted in synergistic single-photon and two-photon processes.. This work demonstrates a new paradigm for achieving ultrafast, broadband, and energy-efficient AOS by heteroatom doping engineering. |
| title | Femtosecond low-threshold all-optical switching enabled by giant broadband optical nonlinearity from heteroatom doping |
| topic | Optics |
| url | https://arxiv.org/abs/2509.08663 |