Optical Potential-Well Array for High-Selectivity, Massive Trapping and Sorting at Nanoscale

Abstract

Optical tweezers are versatile tools capable of sorting microparticles, yet formidable challenges are present in the separation of nanoparticles smaller than 200 nm. The difficulties arise from the controversy on the requirement of a tightly focused light spot in order to create strong optical forces while a large area is kept for the sorting. To overcome this problem, we create a near-field potential well array with connected tiny hotspots in a large scale. This situation can sort nanoparticles with sizes from 100 to 500 nm, based on the differentiated energy depths of each potential well. In this way, nanoparticles of 200, 300, and 500 nm can be selectively trapped in this microchannel by appropriately tuning the laser power. Our approach provides a robust and unprecedented recipe for optical trapping and separation of nanoparticles and biomolecules, such that it presents a huge potential in the physical and biomedical sciences.

Optomechanical Wagon‐Wheel Effects for Bidirectional Sorting of Dielectric Nanoparticles

“…Recently, a near‐field geometry is put forward for the selective optical trapping of PS particles by controlling the magnitude of intensity‐gradient force. [ 42 ] The method allows one to screen out larger (200/300/500 nm) particles from smaller (100/200/400 nm) ones but not vice versa. On the other hand, the extended phase‐gradient trap provides a way for trapping smaller particles, while repelling those of larger size by the radiation pressure.…”

“…The method is self-sustained, without the need for external microfluidic devices or near-field structures fixed in space. [42,[44][45][46][47] As it applies to the most normal case, namely the dielectric nanoparticles, the method could be extended to plasmonic and semiconductor counterparts. [48−50] By revealing the OWWE, our findings endow…”

On‐Chip Optical Detection of Viruses: A Review

“…Optical forces [ 64–66 ] from the strong resonance of cavities in photonic crystals trap single viruses easily from the aqueous medium. Optical trapping has the advantage of noninvasive and is capable to study the HIN1 influenza virus and measure the stoichiometry of antibody‐binding interactions using near‐field light‐scattering technique.…”

Nano-particle transport and the prediction of a valid area to be trapped based on a plasmonic antenna array

“…6,7 As the metal surface plasmon resonance structures with localized strong gradient electric elds can be used to optically trap nanoparticles, [8][9][10][11][12][13] many groups have focused on the optical trapping for a long time. [14][15][16] The optical force on the nanoparticles caused by the evanescent eld can draw the nanoparticles into a 'hot spot'. The structures that are used to produce the 'hot spots' are various, such as coaxial plasmonic apertures, 17 optical antennas 18 and hybrid plasmonic waveguides.…”