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|Title: ||Optical micromanipulation of aerosols|
|Authors: ||Summers, Michael David|
|Supervisors: ||Dholakia, Kishan|
|Issue Date: ||2009|
|Abstract: ||This thesis describes my work on the development of optical trapping
techniques for manipulating airborne particles. Although many of the basic
principles are similar to those used in more conventional colloidal experiments,
there are many differences which have been described and investigated in
detail in this work.
Basic characterisation measurements are made, such as axial Q and sample size
selectivity, for a number of sample liquids in a basic optical tweezers setup.
Performance at 532nm and 1064nm were compared and shown to be very
similar, despite increased absorption in the infrared. A successful method was
developed for the optical trapping of solid aerosol particles, allowing a direct
comparison between similar particles suspended in both the gas and liquid
A single beam levitation trap was developed for transporting liquid aerosols to
allow multiple chemical measurements to be made on a single droplet.
Performance between Gaussian and Bessel beams was compared for various
liquids, with guiding distances of several millimetres being achieved with the
Bessel beam geometry.
An experiment to demonstrate lasing within an optically tweezed droplet was
also performed and spectra were taken. Although strong resonance modes
were evident, the data was not conclusive. However, it is likely that a redesign
of the experiment would be successful.
These techniques have extended research capabilities in the areas of both
optical trapping and atmospheric chemistry, allowing the detailed study of
single aerosol particles in the 1-10 μm range.|
|Publisher: ||University of St Andrews|
|Appears in Collections:||Physics & Astronomy Theses|
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