A Plasmonic Spanner for Metal Particle Manipulation.
Typically, metal particles are difficult to manipulate with conventional optical vortex (OV) tweezers, because of their strong absorption and scattering. However, it has been shown that the vortex field of surface plasmonic polaritons, called plasmonic vortex (PV), is capable of stable trapping and dynamic rotation of metal particles, especially those of mesoscopic and Mie size. To uncover the different physical mechanisms of OV and PV tweezers, we investigated the force distribution and trapping potential of metal particles. In OV tweezers the stronger scattering force causes a positive potential barrier that repels particles, whereas in PV tweezers the dominant gradient force contributes to a negative potential well, resulting in stably trapped particles. Compared with OV, the orbital angular momentum of PV produces an azimuthal scattering force that rotates the trapped particles with more precise radius and position. Our results demonstrate that PV tweezers are superior in manipulation of metal particles.
Institute of Micro and Nano Optics, Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, College of Optoelectronic Engineering, Shenzhen University, Shenzhen, 518060, China.
Yuquan
Y
Zhang
Institute of Modern Optics, Nankai University, Tianjin, 300071, China.
Wei
W
Shi
Institute of Modern Optics, Nankai University, Tianjin, 300071, China.
Zhe
Z
Shen
Institute of Modern Optics, Nankai University, Tianjin, 300071, China.
Zhongsheng
Z
Man
Institute of Micro and Nano Optics, Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, College of Optoelectronic Engineering, Shenzhen University, Shenzhen, 518060, China.
Changjun
C
Min
Southwest Jiaotong University emei campus, Emei, 614202, China.
Junfeng
J
Shen
Institute of Oncology, Tianjin Union Medicine Centre, Tianjin 300121, China.
Siwei
S
Zhu
Optics Research Group, Delft University of Technology, Lorentzweg 1, 2628CJ Delft, The Netherlands.
H Paul
HP
Urbach
Institute of Micro and Nano Optics, Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, College of Optoelectronic Engineering, Shenzhen University, Shenzhen, 518060, China.
Xiaocong
X
Yuan