ORCID Profile
0000-0002-3017-8964
Current Organisation
The Francis Crick Institute
Does something not look right? The information on this page has been harvested from data sources that may not be up to date. We continue to work with information providers to improve coverage and quality. To report an issue, use the Feedback Form.
Publisher: IOP Publishing
Date: 12-06-2009
Publisher: Royal Society of Chemistry (RSC)
Date: 2012
DOI: 10.1039/C2CP42925J
Abstract: In this paper we explore the trapping of aerosol droplets using an annular beam, formed by blocking the central portion of a Gaussian beam, and quantify the improvements over conventional Gaussian beam traps. Recent work on the modelling of single aerosol dynamics within an optical tweezer trap [Burnham et al., Journal of the Optical Society of America B, 2011, 28, 2856-2864] has indicated that the use of annular beams can allow smaller droplets to be trapped, which we experimentally verify. We also demonstrate that annular beams allow droplets to be trapped at higher powers, and with reduced axial displacement with increasing power, than Gaussian beams. We confirm these results, due to a reduction in the axial scattering forces, using this theoretical model. Finally back focal plane interferometry is used to determine the axial and lateral trap stiffnesses for a series of droplets, showing a significant increase in the axial : lateral trap stiffness ratio from 0.79 ± 0.04 to 1.15 ± 0.04 when an annular beam is used.
Publisher: AIP Publishing
Date: 21-07-2008
DOI: 10.1063/1.2952374
Abstract: We demonstrate that holographically generated optical patterns offer greater flexibility for the thermocapillary control of water droplets than Gaussian spots droplets can be stopped in faster flows while using less optical intensity when the surface tension variations are created by line patterns instead of single spots. Further, experiments are performed making use of variable light patterns to achieve controlled droplet routing in a four-way cross microfluidic channel. Finally, multiple droplet storage is demonstrated as well as changing drop order.
Publisher: IEEE
Date: 06-2007
Publisher: IEEE
Date: 09-2009
Publisher: Optica Publishing Group
Date: 25-02-2010
Publisher: IEEE
Date: 06-2007
Publisher: American Physical Society (APS)
Date: 05-07-2007
Publisher: SPIE
Date: 13-09-2007
DOI: 10.1117/12.736448
Publisher: SPIE
Date: 13-09-2007
DOI: 10.1117/12.733716
Publisher: SPIE
Date: 28-08-2008
DOI: 10.1117/12.794855
Publisher: Royal Society of Chemistry (RSC)
Date: 2009
DOI: 10.1039/B814545H
Abstract: Arrays of optically tweezed aerosol droplets, each of sub-picolitre volume, are manipulated by holographic optical tweezers and characterised by cavity enhanced Raman spectroscopy. A spatial light modulator is employed to generate arrays of optical traps from a single laser beam and to control the array dimensions and relative trap positions. Comparative hygroscopicity measurements are performed concurrently on five trapped droplets by monitoring the evolving size of each droplet. This is extended to the controlled coalescence of an array of droplets accompanied by spectroscopic measurements. These data represent the first ever simultaneous measurements of the evolving composition and size of an array of aerosol droplets. We consider the possibility of using aerosol arrays as a platform for studying chemical reactions in sub-picolitre volumes, exploiting the versatility of aerosol arrays for performing optical digital microfluidic operations accompanied by micro-total analysis.
Publisher: American Physical Society (APS)
Date: 12-07-2007
Publisher: SPIE
Date: 31-08-2006
DOI: 10.1117/12.683635
Publisher: American Physical Society (APS)
Date: 17-11-2010
Publisher: Optica Publishing Group
Date: 05-2006
DOI: 10.1364/OE.14.004176
Abstract: We demonstrate the use of holographic optical tweezers for trapping particles in air, specifically aerosol droplets. We show the trapping and manipulation of arrays of liquid aerosols as well as the controlled coagulation of two or more droplets. We discuss the ability of spatial light modulators to manipulate airborne droplets in real time as well as highlight the difficulties associated with loading and trapping particles in such an environment. We conclude with a discussion of some of the applications of such a technique.
Publisher: The Optical Society
Date: 11-11-2011
Publisher: IOP Publishing
Date: 31-07-2009
Publisher: Optica Publishing Group
Date: 14-05-2008
DOI: 10.1364/OE.16.007739
Abstract: We demonstrate a method for the optical trapping of solid aerosol particles. Suspension of silica particles in ethanol allows their delivery to the trapping volume using a commercial medical nebulizer. The ethanol quickly evaporates, leaving the solid particles trapped in air. We use the technique to make comparisons between aerosol and colloid tweezing through power spectra analysis of the particle's positions fluctuations for identical particles trapped in a water or air suspending medium.
Publisher: SPIE
Date: 02-02-2019
DOI: 10.1117/12.794195
Publisher: IEEE
Date: 06-2007
Publisher: IOP Publishing
Date: 24-07-2007
Publisher: Optica Publishing Group
Date: 15-07-2008
DOI: 10.1364/OE.16.011411
Abstract: The vortex emergence process as an integer order Bessel field progresses continuously onto the contiguous higher order Bessel field is studied in detail. We assess the progressive migration of phase singularities and explain the predicted increase in fractional orbital angular momentum content of the beam in terms of this gradual process.
Publisher: IOP Publishing
Date: 19-05-2009
Location: United Kingdom of Great Britain and Northern Ireland
Location: United Kingdom of Great Britain and Northern Ireland
Location: United Kingdom of Great Britain and Northern Ireland
Location: United Kingdom of Great Britain and Northern Ireland
No related grants have been discovered for Daniel Burnham.