Optofluidics

optothermal trapping in air-filled HC-PCF
Radiation pressure resulting from the fundamental mode of a HC-PCF can keep a microparticle trapped at the centre of the core, while propelling it along the fibre. Our experiments in which light scattered by the particle creates a temperature gradient along the fibre, have led to the discovery of an opto-thermal trapping mechanism that is the result of a competition between optical forces and viscous drag caused by a thermally-driven air flow [3]. 

flying particle sensor
We recently introduced a new kind of fibre optic sensor, based on a 'flying-particle' optically trapped and moved to and fro inside a HC-PCF. The transverse displacement of a charged microparticle can be detected by changes in the transmitted light signal, and is used to map electric field patterns near the surface of a multi-element electrode with high spatial resolution. We believe such flying-particle sensors open up a plethora of new opportunities, potentially allowing multiple physical quantities to be mapped with very high positional accuracy over km distances [6].

collaborations

This research was initiated in the group of Philip Russell at the Max Planck institute for the Science of Light in Erlangen, Germany. Our work over the past years builds on several successful collaborations including:  

- Peter Sadler, University of Warwick (photomedicine)
- Anita Jones, University of Edinburgh (photoswitching, fluorescence)
- Bastian Etzold, Peter Wasserscheid, University of Erlangen-Nuremberg (catalysis)
- Graeme Whyte, Heriot Watt University (wavefront shaping)

With state-of-the-art labs in the new Maxwell Centre for the Physical Sciences, the Optofluidics group in NanoPhotonics establishes strong links with expertise in catalytic chemistry, microfluidics, particle technology, and spectroscopy, both within NanoPhotonics and across the School of Physical Sciences.