Throughout the course of her Nuffield Foundation project this summer' Ewa Karczewska will be making updates of her progress on our blog. Her first instalment is below.
Ewa writes: I have started this Nuffield Bursary project by studying the mechanical effect of evanescent optical fields on microscopic particles. I have learned how to set up simple optical path using optical mirrors and lenses, and most importantly I have understood the basic ideas behind the use of the laser light for optical trapping. Having been familiarised with the equipment in the laboratory and having been shown the experiment of array formation and optical binding in evanescent waves carried out by Marios Sergides, I have been using the heating and pulling method for making tapered optical fibres. With this method I have produced several optical fibres of less than 2μm in diameter. Using these fibres I will be trying to trap micron-sized spheres in the evanescent field, but first the efficiency of coupling and light transmission into the fibre must be improved. To do this I have learned how to polish and connectorize optical fibres and measured the transmission efficiency.
|Tapered glass optical fibre|
with 2 micron polystyrene spheres