The 2013 Bragg Lecture will take place on Wed 30 October, and will be given by Prof Paul Chaikin (New York University) on Some small steps towards artificial life.
Abstract: The properties we often associate with living things are motility,
metabolism, self-replication and evolution. According to the Nobel
Laureate Richard Feynman: “What I can’t create, I don’t understand”. We
thought we’d give it a shot - understanding life - and in the process
we’ve made two different systems, one that exhibits both autonomous
motility and metabolism and another which is the first artificial system
that can replicate arbitrarily designed motifs. The first system,
artificial swimmers, provides insight into many natural phenomena such
as a flocking of birds and schooling of fish. The second system uses
diurnal cycles of temperature and light and at present is doubling each
cycle, growing exponentially. It provides a new way of producing many,
many copies of nanoscale devices and may give insights into the origin
of conventional life on earth. We even have initiated an elementary
form of evolution.
Wednesday, 30 October 2013
Wednesday, 23 October 2013
Marios Sergides PhD viva
Congratulations to Optical Tweezers PhD student Marios Sergides who has successfully defended his PhD thesis on Optical manipulation of micro-and nanoparticles using evansecent fields. Marios will be leaving the group to start a postdoc with a Japan Sciety for the Promotion of Science (JSPS) Postdoctoral Fellowship at the Okinawa Institute of Science and Technology (OIST), Japan, in the Light-Matter Interactions Unit under the supervision of Dr Sile Nic Chormaic. Many thanks to Dr Mark Ellerby (UCL) and Dr Valeria Garbin (Imperial College) for acting as examiners.
Well done Dr Sergides, and good luck in Japan!
Well done Dr Sergides, and good luck in Japan!
SPIE Conference Proceedings
Proceedings from the SPIE Optics + Photonics 2013 conference have been published. These include a paper containing calculations by Stephen Simpson (Bristol University) based on our optical binding experiments: S. H. Simpson, P. H. Jones, O. M. Maragò, S. Hanna & M. J. Miles. 'Optical binding of nanowires in counter-propagating beams’, Proc SPIE 8810 Optical Trapping and Optical Micromanipulation X, 881026, doi: 10.1117/12.2024466 (2013).
From the abstrast: We present a computational model for the simulation of optically interacting nano-structures immersed in a viscous fluid. In this scheme, nanostructures are represented by aggregates of small spheres. All optical and hydrodynamic interactions, including thermal fluctuations, are included. As an example, we consider optical binding of dielectric nanowires in counterpropagating plane waves. In particular, the formation of stable, ladder like structures, is demonstrated. In these arrangements, each nanowire lies parallel to the polarization direction of the beams, with their centres of mass colinear.
From the abstrast: We present a computational model for the simulation of optically interacting nano-structures immersed in a viscous fluid. In this scheme, nanostructures are represented by aggregates of small spheres. All optical and hydrodynamic interactions, including thermal fluctuations, are included. As an example, we consider optical binding of dielectric nanowires in counterpropagating plane waves. In particular, the formation of stable, ladder like structures, is demonstrated. In these arrangements, each nanowire lies parallel to the polarization direction of the beams, with their centres of mass colinear.
Tuesday, 1 October 2013
New Group Members
At the start of the new academic year we are welcoming several new members to the Optical Tweezers Group. Chris Richards and Tom Smart are new PhD students who will both be working on the project Exploring Stochastic Thermodynamics with Optical Traps. Chris is a UCL Physics graduate, and worked in the group last year for his MSci project. Tom comes to us from Leeds University via IoP publishing where he worked for 12 months in the editorial office.
Alessandro Magazzu has also joined us as a visiting student for one month under the EU COST Action MP1205 on Optofluidics. Alessandro is in the second year of his PhD at Università degli Studi di Messina, Sicily, and is supervised by Dr Onofrio Marago at the NanoSoft Lab, IPCF-CNR.
Finally Adam Plowman is joining us for his MSci project to investigate the dynamics of artificial micoswimmers.
Monday, 9 September 2013
Entry in Encyclopedia of Optical Engineering
The article on Optical Tweezers has now been published in the Taylor & Francis Encyclopedia of Optical Engineering.
From the abstract: Optical tweezers are devices that use a single, strongly focused laser
beam for the remote, non-contact trapping and manipulation of
microscopic objects. Since the first demonstration of optical tweezers
in 1986, they have become commonly used across physics, chemistry, and
biology for experiments as diverse as measuring the step size of motor
proteins to a demonstration of fluctuations in entropy production in
microscopic systems. In this entry, the mechanism behind optical
tweezers is introduced, followed by a discussion of practical aspects in
the use of optical tweezers, such as data collection and analysis for
quantitative measurements, and the use of holographic optical traps.
Also, a review of one of the many applications of optical tweezers is
presented, namely, the optical trapping of nanoparticles and
nanostructures and their use for imaging and force sensing.
From the abstract: Optical tweezers are devices that use a single, strongly focused laser
beam for the remote, non-contact trapping and manipulation of
microscopic objects. Since the first demonstration of optical tweezers
in 1986, they have become commonly used across physics, chemistry, and
biology for experiments as diverse as measuring the step size of motor
proteins to a demonstration of fluctuations in entropy production in
microscopic systems. In this entry, the mechanism behind optical
tweezers is introduced, followed by a discussion of practical aspects in
the use of optical tweezers, such as data collection and analysis for
quantitative measurements, and the use of holographic optical traps.
Also, a review of one of the many applications of optical tweezers is
presented, namely, the optical trapping of nanoparticles and
nanostructures and their use for imaging and force sensing.
Friday, 6 September 2013
Susan Skelton wins Carey Foster Prize
Congratulations to former Optical Tweezers PhD student Dr Susan Skelton who has won the Carey Foster Prize for 2013 for her thesis Applications of
cylindrical vector beams to optical micromanipulation The Carey Foster Prize is awarded annually for outstanding postgraduate research in Atomic, Molecular, Optical and Positron Physics to a PhD student who has submitted their thesis in the past year.
Susan gained her PhD in February 2013, and is presently a postdoctoral research associate at the Laboratory for Scientific Instrumentation and Engineering (LaSIE) at the University of Osaka, Japan.
Susan gained her PhD in February 2013, and is presently a postdoctoral research associate at the Laboratory for Scientific Instrumentation and Engineering (LaSIE) at the University of Osaka, Japan.
Friday, 23 August 2013
Theoretical Characterisation of Microbubbles Paper
As part of the NPL/UCL/Oxford microbubble trapping collaborative project a paper Theoretical characterisation of the radial and translational motion of coated microbubbles under acoustic excitation has been published as C. J. Harfield et al, J. Phys.: Conf. Ser 457 012001 (2013).
From the abstract: Ultrasound contrast agents, in the form of coated microbubbles, are a powerful tool in current diagnostic imaging. Given their sensitive dynamic response they also have the potential to be used for quantitative measurements of the properties of the surrounding tissue (e.g. percentage perfusion or blood pressure). For this potential to be realised, however, the theoretical descriptions of bubble behaviour, in particular the constitutive equations for the microbubble shell, need to be improved and a method needs to be developed for the accurate characterisation of individual bubbles. In this paper the first steps are taken towards deriving a complete model for the coupled radial and translational motion of a coated bubble. It is then shown that with this model the bubble can be characterised by a unique set of parameters describing the bubble shell corresponding to its viscous and elastic response. This uniqueness will enable the model to be used to interpret experimental data and quantify these parameters for which accurate values are currently lacking but which are critical to predicting bubble response and hence enabling advanced diagnostic applications.
From the abstract: Ultrasound contrast agents, in the form of coated microbubbles, are a powerful tool in current diagnostic imaging. Given their sensitive dynamic response they also have the potential to be used for quantitative measurements of the properties of the surrounding tissue (e.g. percentage perfusion or blood pressure). For this potential to be realised, however, the theoretical descriptions of bubble behaviour, in particular the constitutive equations for the microbubble shell, need to be improved and a method needs to be developed for the accurate characterisation of individual bubbles. In this paper the first steps are taken towards deriving a complete model for the coupled radial and translational motion of a coated bubble. It is then shown that with this model the bubble can be characterised by a unique set of parameters describing the bubble shell corresponding to its viscous and elastic response. This uniqueness will enable the model to be used to interpret experimental data and quantify these parameters for which accurate values are currently lacking but which are critical to predicting bubble response and hence enabling advanced diagnostic applications.
Subscribe to:
Posts (Atom)