Application of plasmonic bowtie nanoantenna arrays for optical trapping, stacking, and sorting.
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 20× 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.
Department of Electrical and Computer Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA.
Brian J
BJ
Roxworthy
Kaspar D
KD
Ko
Anil
A
Kumar
Kin Hung
KH
Fung
Edmond K C
EK
Chow
Gang Logan
GL
Liu
Nicholas X
NX
Fang
Kimani C
KC
Toussaint
D006046:Gold / Q000737:chemistry; D036103:Nanotechnology / Q000295:instrumentation* / Q000379:methods; D052898:Optical Tweezers; D055095:Optics and Photonics
D006046:Gold