Optical Trapping of Gold Nanoparticles in Air

Abstract

Most progress on optical nanoparticle control has been in liquids, while optical control in air has proven more challenging. By utilizing an air chamber designed to have a minimum of turbulence and a single laser beam with a minimum of aberration, we trapped individual 200 to 80 nm gold nanoparticles in air and quantified the corresponding trapping strengths. These results pave the way for construction of metallic nanostructures in air away from surfaces.

Guidable Thermophoretic Janus Micromotors Containing Gold Nanocolorifiers for Infrared Laser Assisted Tissue Welding

“…It is worth to point out that the observed laser based heating presented here is in line with the absorption and heating rates of nanoparticles, whose heating rate was observed not by whole particle motion, but rotational changes, as well as with simulated or lipid bilayer disordering studies 23, 24, 25, 26, 27. Also temperature measurements of Janus particle based cancer treatment agents resulted in similar values like the ones presented here 21.…”

Invited Article: Optical trapping of ultrasmooth gold nanoparticles in liquid and air

“…4(b)]. These predictions are in line with previous studies 4,9 where heating of trapped gold NPs is addressed using the same approximations (i.e., the dielectric function of gold NPs is stationary over elevated temperatures) as in this work. We use these calculated values of temperature together with the integral of the PSD S( f ) to determine the trap stiffness κ using Eq.…”

“…Gold NPs are delivered to the trap through the chamber with a baffle structure based upon the design reported by Jauffred et al 9 Ethanol droplets (3-5 µm in diameter) containing gold NPs (with a concentration of ∼1 × 10 8 m −1 ) are blown into the chamber by a nebulizer (Omron, micro air U22) via a fine nozzle. While droplets travel through two parallel baffles (formed by optically transparent sheets of acetate) with coaxial holes, ethanol is evaporated, thus leaving airborne NPs around the trap site.…”

“…20,21 Recently, trapping of airborne NS gold NPs with diameters from 80 nm to 200 nm has been demonstrated. 9 This work has reported on trap stiffness measurements at a fixed optical power and has provided an initial estimate of the heating associated with particle absorption of the trapping beam. In our study, for the first time, we trap individual US and NS gold NPs (50 nm and 100 nm in diameter) in air for a range of optical power levels up to 0.5 W to reveal the effects of particle morphology.…”

“…[5][6][7] Notably, the chemical properties of gold lead to routes for custom functionalization for biomedically relevant applications. Very recently, a suite of studies have come to the fore exploring the trapping of gold NPs for optical binding, 8 trapping in air, 9 and other studies including their potential use as local heaters or handles in biological investigations. 4 Moreover, laser-induced breakdown of gold NPs can be used for cell poration.…”