Application of Plasmonic Bowtie Nanoantenna Arrays for Optical Trapping, Stacking, and Sorting

作者：Roxworthy Brian J; Ko Kaspar D; Kumar Anil; Fung Kin Hung; Chow Edmond K C; Liu Gang Logan; Fang Nicholas X; Toussaint Kimani C Jr^*

来源：Nano Letters, 2012, 12(2): 796-801.

DOI：10.1021/nl203811q

• Plasmonics
• optical nanoantennas
• optical trapping
• particle sorting
• optical trapping phase diagrams

We present the use of Au bowtie nanoantenna arrays (BNAs) for highly efficient, multipurpose particle manipulation with unprecedented low input power and low-numerical aperture (NA) focusing. Optical trapping efficiencies measured are up to 20X the efficiencies of conventional high-NA optical traps and are among the highest reported to date. Empirically obtained plasmonic optical trapping "phase diagrams" are introduced to detail the trapping response of the BNAs as a function of input power, wavelength, polarization, particle diameter, and BNA array spacing (number density). Using these diagrams, parameters are chosen, employing strictly the degrees-of-freedom of the input light, to engineer specific trapping tasks including (1) dexterous, single-particle trapping and manipulation, (2) trapping and manipulation of two- and three-dimensional particle clusters, and (3) particle sorting. The use of low input power densities (power and NA) suggests that this bowtie nanoantenna trapping system will be particularly attractive for lab-on-a-chip technology or biological applications aimed at reducing specimen photodamage.

• 出版日期2012-2