近日，同济大学物理科学与工程学院王占山教授和程鑫彬教授团队的施宇智特聘研究员与新加坡南洋理工大学刘爱群院士、香港城市大学蔡定平教授、香港科技大学陈子亭院士、新加坡国立大学仇成伟教授等人合作，在物理学权威期刊《物理评论快报》（Physical Review Letters）在线发表题为《椭圆偏振光作用下介电质纳米颗粒中的可逆光力矩》（Inverse Optical Torques on Dielectric Nanoparticles in Elliptically Polarized Light Waves）的论文。该论文首次研究了椭圆偏振光作用下非金属纳米颗粒中的可逆光力矩，揭示了不同偏振态在一定光学入射角的情况下对光力矩的作用机制。
研究亮点
光镊技术利用光力对微小颗粒进行操控，而光的角动量产生的光力矩在其中同样起着至关重要的作用，因而受到了学者们的广泛关注。光力矩在包括量子光机械系统、摩擦学、生物分子的扭转测量、微小搅拌马达的构建在内的物理、生物医学、化学等领域应用广泛。通常情况下，颗粒在圆偏振光中由于自旋角动量的作用会产生方向与自旋角动量一致的光力矩。而“负光力矩”的方向与自旋角动量相反，近期被发现于金属手性颗粒、相位迟滞盘、颗粒簇等系统中。然而，受偶极子模型影响，尚未曾在单个非金属颗粒中发现“负光力矩”。该研究团队利用斜入射的椭圆偏振光，首次在介电质三棱柱中发现了“负光力矩”，揭示了不同偏振态在三棱柱结构中对力矩的作用机制，如图1所示。
图1：斜入射的椭圆偏振光在三棱柱中激发可逆光力矩。结构转角、光的偏振都可以对光力矩产生强烈的作用。
图2：光的椭偏度、颗粒的尺寸和折射率的变化都可以引起“负光力矩”。
该团队将“负光力矩”归因于椭圆偏振分解的不同偏振如p偏振激发下颗粒的偶极子的非中心对称分布，而椭圆偏振分解下的s偏振以及自旋角动量总是引起“正光力矩”。同时，该团队发现该“负光力矩”与光的椭偏度、颗粒的大小和折射率关系密切，如图2所示。尤其，当四分之一波片的偏转角越小，即光更趋向于p偏振，或颗粒的折射率越高，都越容易激发“负光力矩”。相反，颗粒的吸收则会产生“正光力矩”，进而削弱“负光力矩”的作用。而颗粒的尺寸，包括三角的边长和厚度都会对光力矩产生很大的影响，如图3所示。
图3：颗粒的尺寸对光力矩的影响。
该团队还发现，通过简单地调节光的入射角，“正光力矩”和“负光力矩”可以实现轻松切换。这种“负光力矩”将会在传统的颗粒旋转实验中导致颗粒静止，从而影响相关实验的进行，与传统利用带有自旋角动量或轨道角动量的光场旋转颗粒的实验有所不同。该研究首次揭示了不同倾斜入射的椭圆偏振光对介电质颗粒中的光力矩的影响，在光和物质的相互作用、物理和生物医学等领域有着重要的意义。
论文信息
同济大学物理科学与工程学院施宇智特聘研究员为论文第一作者兼共同通讯作者，团队负责人之一程鑫彬教授参与了研究，新加坡南洋理工大学刘爱群院士和新加坡国立大学仇成伟教授是论文共同通讯作者。该研究得到了同济大学科研启动经费和新加坡科研项目的支持。
论文链接：
https://link.aps.org/doi/10.1103/PhysRevLett.129.053902
施宇智特聘研究员自2018年以来在光流控光镊操控领域发表的代表性研究成果如下：
1. Yuzhi Shi, Sha Xiong*, Lip Ket Chin, Jingbo Zhang, Wee Ser, Jiuhui Wu, Tianning Chen, Zhenchuan Yang, Yilong Hao, Bo Liedberg, Peng Huat Yap, Din Ping Tsai, Cheng-Wei Qiu* and Ai Qun Liu*, "Nanometer-precision Linear Sorting with Synchronized Optofluidic Dual Barriers," Science Advances 4, eaao0773, 2018.
2. Yuzhi Shi, Sha Xiong*, Yi Zhang, Lip Ket Chin, Yan-Yu Chen, Jingbo Zhang, Tianhang Zhang, Wee Ser, Andreas Larsson, Siau Hoi Lim, Jiuhui Wu, Tianning Chen, Zhenchuan Yang, Yilong Hao, Bo Liedberg, Peng Huat Yap, Kuan Wang, Din Ping Tsai, Cheng-Wei Qiu* and Ai Qun Liu*, "Sculpting nanoparticle dynamics for single-bacteria-level screening and direct binding-efficiency measurement," Nature Communications 9, 815, 2018. [Highlighted by Nature Review Materials, "Optofluidics: You never hop alone", Nature Reviews Materials 3, 18011 (2018)].
3. Yuzhi Shi#, Tongtong Zhu#, Tianhang Zhang, Alfredo Mazzulla, Din Ping Tsai, Weiqiang Ding, Ai Qun Liu, Gabriella Cipparrone, Juan José Sáenz and Cheng-Wei Qiu*, “Chirality-assisted lateral momentum transfer for bidirectional enantioselective separation”, Light: Science & Applications, 9, 62, 2020.
4. Yuzhi Shi*, Tongtong Zhu, Ai Qun Liu*, Lei-Ming Zhou, Manuel Nieto-Vesperinas, Amir Haminger, Jingquan Liu, Din Ping Tsai, Zhenyu Li, Weiqiang Ding, Fan Wang, Hang Li, Qinghua Song, Xiaohao Xu, Baojun Li, Xinbin Cheng, Pin Chieh Wu, Che Ting Chan and Cheng-Wei Qiu*, “Inverse optical torques on dielectric nanoparticles in elliptically polarized light waves”, Physical Review Letters 129, 053902, 2022.
5. Yuzhi Shi, Haitao Zhao, Kim Truc Nguyen, Yi Zhang*, Lip Ket Chin, Tongtong Zhu, Yefeng Yu, Hong Cai, Peng Huat Yap, Patricia Yang Liu, Sha Xiong, Jingbo Zhang, Cheng-Wei Qiu, Che Ting Chan and Ai Qun Liu*, “Nanophotonic Array-Induced Dynamic Behavior for Label-Free Shape-Selective Bacteria Sieving”, ACS Nano, 13, 10, 12070-12080, 2019.
6. Yuzhi Shi, Yongfeng Wu, Lip Ket Chin*, Zhenyu Li, Jingquan Liu, Mu Ku Chen, Shubo Wang, Yi Zhang, Patricia Yang Liu, Xiaohong Zhou, Hong Cai, Wanzhen Jin, Yefeng Yu, Ruozhen Yu, Wei Huang, Peng Huat Yap, Limin Xiao, Wee Ser, Thi Thanh Binh Nguyen, Yu-Tsung Lin, Pin Chieh Wu, Jiayan Liao, Fan Wang, Che Ting Chan*, Yuri Kivshar*, Din Ping Tsai* and Ai Qun Liu*, “Multifunctional Virus Manipulation with Large-Scale Arrays of All-Dielectric Resonant Nanocavities”, Laser & Photonics Review, 2100197, 2022.
7. Yuzhi Shi, Haitao Zhao, Lip Ket Chin, Yi Zhang, Peng Huat Yap, Wee Ser, Cheng-Wei Qiu* and Ai Qun Liu*, “Optical Potential-Well Array for High-Selectivity, Massive Trapping and Sorting at Nanoscale”, Nano Letters, 20, 5193-5200, 2020.
8. Yuzhi Shi*, Lei-Ming Zhou, Ai Qun Liu*, Manuel Nieto-Vesperinas, Tongtong Zhu, Amir Hassanfiroozi, Jingquan Liu, Hui Zhang, Din Ping Tsai, Hang Li, Weiqiang Ding, Weiming Zhu, Ye Feng Yu, Alfredo Mazzulla, Gabriella Cipparrone, Pin Chieh Wu, C. T. Chan, and Cheng-Wei Qiu*, “Superhybrid Mode-Enhanced Optical Torques on Mie-Resonant Particles”, Nano Letters, 22, 1769-1777, 2022.
9. Yuzhi Shi, Qinghua Song*, Ivan Toftul, Tongtong Zhu, Yefeng Yu*, Weiming Zhu*, Din Ping Tsai, Yuri Kivshar* and Ai Qun Liu*, “Optical manipulation with metamaterial structures”, Applied Physics Reviews, 2022, in production, to be highlighted in AIP Scilight.
10. Tongtong Zhu, Yuzhi Shi*, Weiqiang Ding, Din Ping Tsai, Tun Cao, Ai Qun Liu, Manuel Nieto-Vesperinas, Juan José Sáenz, Pin Chieh Wu and Cheng-Wei Qiu*, “Extraordinary Multipole Modes and Ultra-Enhanced Optical Lateral Force by Chirality”, Physical Review Letters, 125, 043901, 2020.
11. Jin Qin, Shibin Jiang, Zhanshan Wang, Xinbin Chen, Baojun Li, Yuzhi Shi*, Din Ping Tsai*, Ai Qun Liu*, Wei Huang* and Weiming Zhu*, “Metasurface Micro/Nano Optical Sensors: Principles and Applications”, ACS Nano, 2022, accepted.
12. Yuzhi Shi, Tongtong Zhu, Kim Truc Nguyen, Yi Zhang, Sha Xiong, Peng Huat Yap, Wee Ser, Shubo Wang, Cheng-Wei Qiu, C. T. Chan* and Ai Qun Liu*, “Optofluidic Micro-Engine in A Dynamic Flow Environment via Self-Induced Back-Action”, ACS Photonics, 7, 1500–1507, 2020.
13. Yuzhi Shi*, Kim Truc Nguyen, Lip Ket Chin, Zhenyu Li, Limin Xiao, Hong Cai, Ruozhen Yu*, Wei Huang, Shilun Feng, Peng Huat Yap, Jingquan Liu*, Yi Zhang*, and Ai Qun Liu*, “Trapping and detection of single viruses in an optofluidic chip”, ACS Sensors, 6, 3445-3450, 2021.
14. Yuzhi Shi*, Zhenyu Li, Patricia Yang Liu, Binh Thi Thanh Nguyen, Wenshuai Wu, Qianbin Zhao, Lip Ket Chin*, Minggui Wei, Peng Huat Yap*, Xiaohong Zhou, Hongwei Zhao, Dan Yu, Din Ping Tsai and Ai Qun Liu*, “On-Chip Optical Detection of Viruses: A Review,” Advanced Photonics Research, 2021, 2000150, 2021.
15. Lip Ket Chin#*, Yuzhi Shi# and Ai Qun Liu*, "Optical Forces in Silicon Nanophotonics and Optomechanical Systems: Science and Applications," Advanced Devices & Instrumentation, 1964015, 2020.
16. S. Luo, Y. Z. Shi*, L. K. Chin, P. E. Hutchinson, Y. Zhang, G. Chierchia, H. Talbot, X. D. Jiang, T. Bourouina*, and A. Q. Liu*, “Machine-Learning-Assisted Intelligent Imaging Flow Cytometry–A Review,” Advanced Intelligent Systems 3, 2100073, 2021.
17. Hang Li, Yongyin Cao, Bojian Shi, Tongtong Zhu, Yong Geng, Rui Feng, Lin Wang, Fangkui Sun, Yuzhi Shi, Mohammad Ali Miri, Manuel Nieto-Vesperinas, Cheng-Wei Qiu*, and Weiqiang Ding*, “Momentum-topology-induced optical pulling force”, Physical Review Letters, 124, 143901, 2020.
18. Hang Li, Yongyin Cao, Lei-Ming Zhou, Xiaohao Xu, Tongtong Zhu, Yuzhi Shi, Cheng-Wei Qiu* and Weiqiang Ding*, “Optical Pulling Forces and Their Applications”, Advances in Optics and Photonics, 12, 288-366, 2020.
（转载自两江科技评论公众号）
