摘要
Optical methods to manipulate and detect nanoscale objects are highly desired in both nanomaterials and molecular biology fields.Optical tweezers have been used to manipulate objects that range in size from a few hundred nanometres to several micrometres.The emergence of near-field methods that overcome the diffraction limit has enabled the manipulation of objects below 100 nm.A highly free manipulation with signal-enhanced real-time detection,however,remains a challenge for single sub-100-nm nanoparticles or biomolecules.Here we show an approach that uses a photonic nanojet to perform the manipulation and detection of single sub-100-nm objects.With the photonic nanojet generated by a dielectric microlens bound to an optical fibre probe,three-dimensional manipulations were achieved for a single 85-nm fluorescent polystyrene nanoparticle as well as for a plasmid DNA molecule.Backscattering and fluorescent signals were detected with the enhancement factors up to~103 and~30,respectively.The demonstrated approach provides a potentially powerful tool for nanostructure assembly,biosensing and single-biomolecule studies.
基金
supported by the Program for Changjiang Scholars and Innovative Research Team in University(IRT13042)
the National Natural Science Foundation of China(No.61205165).
