title: Stable optical trapping and sensitive characterization of nanostructures using standing-wave Raman tweezers.
abstract: Optical manipulation and label-free characterization of nanoscale structures open up new possibilities for assembly and control of nanodevices and biomolecules. Optical tweezers integrated with Raman spectroscopy allows analyzing a single trapped particle, but is generally less effective for individual nanoparticles. The main challenge is the weak gradient force on nanoparticles that is insufficient to overcome the destabilizing effect of scattering force and Brownian motion. Here, we present standing-wave Raman tweezers for stable trapping and sensitive characterization of single isolated nanostructures with a low laser power by combining a standing-wave optical trap with confocal Raman spectroscopy. This scheme has stronger intensity gradients and balanced scattering forces, and thus can be used to analyze many nanoparticles that cannot be measured with single-beam Raman tweezers, including individual single-walled carbon nanotubes (SWCNT), graphene flakes, biological particles, SERS-active metal nanoparticles, and high-refractive semiconductor nanoparticles. This would enable sorting and characterization of specific SWCNTs and other nanoparticles based on their increased Raman fingerprints.
authors.affiliation: School of Electronic Engineering, Dongguan University of Technology, Dongguan, Guangdong, P.R. China.
authors.forename: Mu-Ying
authors.initials: MY
authors.lastname: Wu
authors.affiliation: School of Electronic Engineering, Dongguan University of Technology, Dongguan, Guangdong, P.R. China.
authors.forename: Dong-Xiong
authors.initials: DX
authors.lastname: Ling
authors.affiliation: Department of Physics, East Carolina University, Greenville, North Carolina 27858-4353, USA.
authors.forename: Lin
authors.initials: L
authors.lastname: Ling
authors.affiliation: Department of Physics, East Carolina University, Greenville, North Carolina 27858-4353, USA.
authors.forename: William
authors.initials: W
authors.lastname: Li
authors.affiliation: School of Electronic Engineering, Dongguan University of Technology, Dongguan, Guangdong, P.R. China.|Department of Physics, East Carolina University, Greenville, North Carolina 27858-4353, USA.
authors.forename: Yong-Qing
authors.initials: YQ
authors.lastname: Li