Probing the optical chiral response of single nanoparticles with optical tweezers

Abstract

We propose an enantioselective scheme to sort homogeneous chiral particles using optical tweezers. For a certain range of material parameters, we show that a highly focused circularly-polarized laser beam traps particles of a specific chirality selected by the handedness of the trapping beam. Furthermore, by applying a transverse Stokes drag force that displaces the trapped particle off-axis, we allow for the rotation of the particle center-of-mass around the trapping beam axis. The rotation angle is highly dependent on the handedness of the trapped particle and is easily measurable with standard video-microscopy techniques, allowing for an alternative mechanism for chiral resolution. Our platform not only allows for enantioselection of particles dispersed in solution but also paves the way to the characterization of the chiral parameter of individual, homogeneous chiral microspheres using optical tweezing.

arXiv comment9 pages, 5 figures

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• Chiral plasmonics
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• Theory of Optical Tweezers
• Transverse Chiral Optical Forces by Chiral Surface Plasmon Polaritons
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• Three-dimensional enantiomeric recognition of optically trapped single chiral nanoparticles
• Plasmonic lateral forces on chiral spheres
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Cited by in corpus (6)

• Trapping microparticles in a structured dark focus
• Precise in situ radius measurement of individual optically trapped microspheres using negative optical torque exerted by focused vortex beams
• Probing the chirality of a single microsphere trapped by a focused vortex beam through their orbital period
• Tailoring radiation pressure on infinite slab using pair of non-collinear plane waves
• Circular Dichroism without absorption in isolated chiral dielectric Mie particles
• Gain-assisted optical tweezing of plasmonic and large refractive index microspheres