FEIT Research Project Database

Optical nanotweezers

Project Leader: Kenneth Crozier
Staff: Kenneth Crozier
Sponsors: Australian Research Council
Primary Contact: Kenneth Crozier (kenneth.crozier@unimelb.edu.au)
Keywords: nanoengineered materials; nanofabrication; nanophotonics; nanostructured materials; nanostructured surface
Disciplines: Electrical & Electronic Engineering
Domains: Convergence of engineering and IT with the life sciences

Optical tweezers use the forces exerted by focused laser beams to trap and manipulate particles. Conventional optical tweezers employ lenses to focus laser beams. Due to the diffraction limit, these can only focus light to spots no smaller than roughly half the wavelength. This sets a limit to the force that can be exerted by conventional optical tweezers on a particle of a given size, with a given refractive index, and a given laser power. This makes it challenging to trap very small particles. We have previously overcome this limitation via using nanostructures, rather than just lenses, to focus light. These have included gold nanostructures (eg: Nature Communications 2, 469 (2011)), silicon photonic crystals (eg: Nano Letters 13, 559 (2013)) and silicon micro-ring resonators (eg: Nano Letters 10, 2408 (2010)). We have recently demonstrated that Si nanoantennas offer exciting possibilities for optical nanotweezers (ACS Photonics 5, 4993 (2018) and Opt Expr 27, 4034 (2019)). We are furthermore employing algorithms as a means for boosting performance (Opt Lett 44, 5250 (2019)).

PhD projects are available on developing new types of nanostructures for optical tweezers, and their integration with microfluidic chips. Projects will have both experimental and theory/simulation components. 

Further information: http://blogs.unimelb.edu.au/crozier-group/

Gold nanopillar optical tweezer