PhD studentship available

A PhD studentship is available as part of a joint project between the National Physical Laboratory, University College London (UCL) and the University of Oxford, aimed at the trapping and manipulation of microbubbles in optical and acoustical fields, to transform them into micro-sensors. The project already employs a PhD student for the theoretical part: we are currently recruiting a student for the experimental side of the project.

The work will be mainly conducted at NPL under the direction of Dr Gianluca Memoli, and the student will be registered for a PhD with Dr Philip Jones, at the Department of Physics & Astronomy, University College London.

The studentship is available for three years, starting in early 2012 and will pay a stipend and fees at a rate applicable for UK and EU students.

Candidates should have a degree in Physics or Engineering and previous experimental experience (with lasers or ultrasound or microfluidics) would be a clear advantage.

The National Physical Laboratory (NPL) is one of the UK's leading science facilities and research centres. It is a world-leading centre of excellence in developing and applying the most accurate standards, science and technology available.

NPL occupies a unique position as the UK's National Measurement Institute and sits at the intersection between scientific discovery and real world application. Its expertise and original research have underpinned quality of life, innovation and competitiveness for UK citizens and business for more than a century.

NPL is based in a unique research environment which is located in pleasant surroundings on the edge of Bushy Park in south-west London. We have a host of onsite facilities including a subsidised crèche, restaurant, and a sports and social club.

NPL Management Limited is committed to supporting their people to develop both personally and professionally and is committed to equal opportunities.

To apply for this position, please send your CV and any other relevant information to:

Dr Gianluca Memoli
Tel: +44 20 8943 6062
Email: gianluca.memoli@npl.co.uk

The cosing date for aplications is 31 December 2011.

Optical trapping of porous silicon nanoparticles

Our paper Optical trapping of proous silicon nanoparticles has now been published as M. G. Donato et al, Nanotechnology 22 505704 (2011).

Abstract: Silicon nanoparticles obtained by ball-milling of a 50% porosity silicon layer have been optically trapped when dispersed in a water–surfactant environment. We measured the optical force constants using linearly and radially polarized trapping beams finding a reshaping of the optical potential and an enhanced axial spring constant for the latter. These measurements open perspectives for the control and handling of silicon nanoparticles as labeling agents in biological analysis and fluorescence imaging techniques.

Harrie Massey Lecture

Prof Niek van Hulst (ICFO Barcelona) is visiting the UCL Physics Department today and giving the annual Harrie Massey Lecture on the topic of Coherent control of single molecules, complexes and nanoantennae.

Abstract: The observation of quantum mechanical effects in biological systems, such as light-harvesting antennae, has opened a lively debate as to the role of coherences in natural systems. Traditionally, such coherences are probed by manipulating quantum interference effects with shaped laser pulses. Yet the intrinsic structural inhomogeneity and environmental fluctuations of complex systems at ambient conditions average out most oscillatory spectroscopic features. Only by “single molecule detection” one can hope to catch a glimpse through the disorder. This lecture will present coherent control of single molecules, allowing both observation and manipulation of vibrational wave-packet interference and Rabi-oscillations in individual molecules at ambient conditions. The single-molecule approach ensures that the ultimate degree of coherent control can be realized. We have applied our novel method to single light-harvesting complexes and optical nanoantennas. Recent results on ultrafast quantum coherent energy transfer and femtosecond control of nanoscale hotspots will be presented.

Visit by Onofrio Marago and Maria Grazia Donato

This week (21-26 November) Onofrio Marago and Maria Grazia Donato from the NanoSoft Lab, IPCF-CNR (Messina) are visiting our group at UCL.  Our groups have a long-running collaboration, and exchange visits are funded by the Royal Society as part of our International Joint Project on Photonic Force Microscopy.

Microbubble User Group Meeting

The latest Microbubble User Group (microBUG) meeting is being held on Wed 16 November at Imperial College.  The programme of talks for the day is:

David (single bubble characterisation)
Susan (optical trapping of bubbles)
Terence (acousto-optic bubble characterisation)
Virginie (bubble formation in decompression sickness)
Jonathan (charactertization of adherent microbubbles)
Grace (stability of gold coated bubbles)
IEEE meeting highlights

The meetings are held in the Royal School of Mines, and hosted by Mengxing Tang.

Visit to NanoSoft Lab, IPCF-CNR (Messina)

Phil is spending the week of 07-11 November visiting Onofrio Marago and colleagues at the NanoSoft Lab, IPCF-CNR (Messina).  Our groups have a long-running collaboration, and exchange visits are funded by the Royal Society as part of our International Joint Project on Photonic Force Microscopy.

Physics Department Colloquium

Dr Gavin Crooks (Lawrence Berkeley National Laboratory, University of California Berkeley) will be giving this term's Departmental Colloquium today, Wed 19 Oct, on Statistical Thermodynamics and the Breaking of Time Symmetry.

Abstract: The irreversible dissipation of energy is directly related to the breaking of time reversal symmetry. I will discuss some of the implication of these phenomena to microscopic, driven non-equilibrium systems, such as single molecular force-extension experiments, biological molecular motors and artificial photosynthesis.

Departmental Teaching Prize

Phil has won the Department of Physics and Astronmy's Departmental Teaching Prize for 2011.  In 2010-11 Phil was lecturing the course Lasers & Modern Optics (PHAS3443) for third and fourth year undergraduates.  The prize-giving ceremony will be held on Friday 28 October.  Earlier this year Phil also won the Mathematical and Physical Sciences (MAPS) Faculty Teaching Award.

New Group Members

Kelly Thorneycroft has joined the UCL Optical Tweezers Group for her MSci project.  Kelly is a fourth year undergraduate studying Natural Sciences and will be working on optical trapping and binding experiments and biophysical applications.

Electromagnetic and Light Scattering XIII

The latest conference in the series 'Electromagnetic and Light Scattering' (ELS XIII) is being held in Taormina, Sicily from 26-20 September.

Phil will be giving an invited talk about the UCL Optical Tweezers Group's research on Optical Trapping and Optical Binding Using Cylindrical Vector Beams.  The book of extended abstracts of all the conference presentations is published in a special issue of Atti della Accademia Peloritana dei Pericolanti Volume 89, Supplement No. 1 (2011).

Fano-Doppler Cooling paper

Our paper 'Fano-Doppler laser cooling of hybrid nanostructures' is now published in ACS Nano 5 7354-7361 (2011).

Laser cooling the center-of-mass motion of systems that exhibit Fano resonances is discussed. We find that cooling occurs for red or blue detuning of the laser frequency from resonance depending on the Fano factor associated with the resonance. The combination of the Doppler effect with the radiation cross-section quenching typical of quantum interference yields temperatures below the conventional Doppler limit. This scheme opens perspectives for controlling the motion of mesoscopic systems such as hybrid nanostructures at the quantum regime and the exploration of motional nonclassical states at the nanoscale.

Nuffield Bursary Update (3)

Throughout the course of her Nuffield Foundation project this summer Ewa Karczewska will be making updates of her progress on our blog.  Her final instalment is below.

Ewa writes: During the 8-week project with the UCL Optical Tweezers Group I have learnt a great deal about the laboratory work as well as the current experiments run in it, which focus on the evanescent field and the micro- and nano- structures trapping. I have also gain knowledge about the evanescent wave and the different optical fibre modes.
My research was focused on the thin fibre fabrication using the “heating and pulling”method. The light (λ = 1064nm) was coupled to the tapered fibre so that the evanescent field near the taper region was created. That field was then tested with the micro-sized spheres. When the field was strong enough and the surface of the fibre was smooth enough, the spheres were observed to move along the fibre along the direction of the light propagation.
Overall, I have managed to obtain an efficient method of obtaining thin (about 1.5μm in diameter) optical fibres using the “heating and pulling” method and observe the spheres of 2μm to move along the fibre once the laser light was coupled through it. When the laser light was coupled from both sides of the fibre I could move the spheres in two directions and also balanced the two beams so that the spheres stayed in place.
I have also investigated the behaviour of the micron-sized spheres when the polarisation of the trapping light of an optical tweezers was changed from linear to circular polarisation as well as from radial to azimuthal polarisation.
That project gave me a valuable experience and a great insight into the research work, which will be very useful in my future study for PhD.

From September Ewa will be studying for the third year of her degree as a year abroad in Toronto University.

Nuffield Bursary Update (2)

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: For the past two weeks, I have been investigating and making improvements to the flame brushing method, which then allowed me to obtain the fibres of less than 2µm in diameter. Therefore, after the study on how to make a good coupling between two optical fibres using the splices, the laser beam was coupled into the fibre and the nearby spheres of 2µm in diameter have been observed to move along the fibre in the direction of the light propagation. The spheres were observed to accelerate in the thinnest part of the fibre. When the laser beam was split into two and coupled to each end of the fibre, it was possible to move the spheres in both directions by changing the intensity of the light coupled to each end.  Also it has been observed that if the fibre breaks in the thin part and the laser beam is coupled into it, the spheres accelerate and shoot off from the broken end.

Above you can see a movie of 2µm diameter polystyreen microspheres propelled along a tapered optical fibre in the evanescent field of the guided laser beam.  More movie can be found on our YouTube Channel.

Jeremy Baumberg seminar

Professor Jeremy Baumberg (Cambridge University) will be giving the CMMP/LCN seminar on NanoAssembly on the kilometre scale for NanoPhotonics, Wed 22 Jun 11

Abstract: New photonic properties are produced in materials which are assembled from diverse combinations of metals, semiconductors and dielectrics that are periodically structured on the 100nm-scale, with a wealth of potential applications ranging from communications to bio-sensing. However producing such nanomaterials on the mass-scale is far from trivial as three-dimensional structures are very hard for traditional lithography, and self-assembly has to date been a lab-scale tricky process.

Here we concentrate on a new range of structural colour nanomaterials which can be mass produced as films on the kilometre scale. While most man-made (and natural) colours exploit dye absorption, there is strong interest in avoiding these carcinogenic and UV-bleached chemicals. Alternative structural colours are produced from periodic wavelength-scale-sized transparent components, and thus are benign, long-lived, and possess new optical features. We create polymer photonics crystals made of cross-linked polymer spheres dispersed in a soft elastomeric matrix, using a novel industrially-scalable shear-based nano-assembly. Simply tuning the size of the spheres changes the colour across the entire visible spectrum, while optimised shearing creates single-domain opal films. Stretching these unusual elastomeric photonic crystals breaks their traditional optical scattering selection rules, and enables many applications. We demonstrate a wide variety of new optical properties based on the resonant scattering phenomena.

Faculty Teaching Award

Phil has won the Mathematical and Physical Sciences (MAPS) Faculty Teaching Award for 2011, shared with Prof Ted Johnson from the Department of Mathematics.  The MAPS Faculty comprises the departments of Chemistry, Earth Sciences, Mathematics, Natural Sciences, Physics & Astronomy, Science & Technology Studies, Space & Climate Physics, Statistical Science and the London Centre for Nanotechnology, and the award is made annually in recognition of outstanding provision of teaching within the faculty.  This year Phil was lecturing the course PHAS3443 Lasers & Modern Optics.

Nuffield Bursary Update

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.



Tapered glass optical fibre
with 2 micron polystyrene spheres 

 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.

UCL Science Centre Lecture

On Friday 10 June Phil is giving a lecture for the UCL Science Centre on Fifty Years of the Laser.  The UCL Science Centre organises a series of lectures aimed at 6th form students (and their teachers) on a wide variety of subjects.

Abstract: In this lecture we will review the history of the laser: from Einstein's early predictions about "amplified light", through their invention fifty years ago, when they were considered "a solution looking for a problem", to their widespread use today in applications such as telecommunications and holography. Along the way we will highlight some of the fascinating science and technology that the invention of the laser has made possible, and also showcase some of the current research from the UCL Department of Physics that uses lasers to trap and manipulate particles, to cool matter to nearly absolute zero or to probe the structure and function of biological molecules that are fundamental to life.

Lectures take place at 6.30pm in the Harrie Massey Lecture Theatre and last for 60 minutes, followed by a 30 minute question-and-answer session.

New group members

Ewa Karczewska is joining the UCL Optical Tweezers Group today for an eight week research project funded by the Nuffield Foundation.  The foundation provides research bursaries for undergraduate students considering a career in research to gain experience in a research lab over the summer vacation.  The Optical Twezeers Group has peviously hosted three Nuffield bursary students: Muddassar Rashid (2008), Alex Dunning (2009) and Radhika Patel (2010).

Ewa is a second year undergraduate student at UCL, studying for an MSci degree in Physics.  She will be contributing to a number of different projects presently running in the group, and making regular updates of her progress on this blog.

Andrei Rode visit and seminar

This week Prof Andrei Rode from the Laser Physics Centre of the Australian National University, Canberra is visiting.  While here he will also be giving an AMOP Physics seminar on Optical vortices: Trapping of particles and material processing.

Abstract: In physics and biology, manipulation of microscopic objects achieved remarkable precision and functionality using very small radiation pressure of light and dipole-induced gradient forces, so called optical tweezers.  Stable trapping of absorbing particles in air was not achieved till now due to the dominance of forces from thermal interaction of the laser-irradiated particle with the molecules of ambient gas.  We address this challenge by developing a touch-free optical trapping of particles suspended in air with optical vortices.  The ability to guide absorbing particles along the vortex core in a stable and controlled manner can be employed further for high-accuracy manipulation of particles in three dimensions.

We also developed a femtosecond vortex beam converter where polarization singularities are created when the beam propagates through a birefringent crystal, to produce sub-micron ring structures on the surface of fused silica and glass samples. We employ this technique to generate optical vortex as well as radially (TM) and azimuthally (TE) polarized fs-laser pulses for sub-µm structuring of glass samples.

Interaction of tightly focused multiple fs-pulses with transparent media allows one to imprint their local polarization pattern with sub-wavelength resolution, including the presence of the longitudinal component of electric field.  The materials’ response to the state of polarization of high intensity light fields has been used to map the complex vector structure in the focal volume of radially and azimuthally polarized fs-laser pulses.

Nuffield Bursary Award

Ewa Karczewska has been awarded a Nuffield Foundation Undergraduate Research Bursary to work in the UCL Optical Tweezers Group this summer. This scheme allows UK undergraduates to gain research experience by providing funding for up to eight weeks to complete a research project during the summer vacation. We have hosted three previous Nuffield Foundation Bursary students: Muddassar Rashid (2008) who worked on synthesis and properties of polarisation vortex beams, Alex Dunning (2009) who performed calculations on the properties of optical nanofibres and is now studying for a PhD at Southampton University, and Radhika Patel (2010) who worked on photonic force microscopy experiments and is taking her final exams this year.

Optical Trapping Applications

Next week Phil, Susan and Marios will all be attending the OSA Optical Trapping Applications conference in Monterey, CA.  Phil will be giving a talk about our work on trapping with novel beams, and Susan and Marios will be presenting posters on their research projects.

Visit by Onofrio Marago

Onofrio Marago (NanoSoft Lab, IPCF-CNR, Messina) is visiting the group this week, 7-11 March 2011.

Onofrio has a long-running collaboration with the UCL Optical Tweezers Group and exchange visits between UCL and NanoSoft Lab are presently funded by our Royal Society International Joint Project.

Left: Onofrio adjusting the evanescent-wave optical binding experiment.

NPL Annual Review

The NPL-UCL Microbubble Project is featured in the latest NPL Annual Review, 110 Years of Impact.

Measuring with microbubbles

NPL is working with University College London on a fascinating project which investigates the dynamics of microbubbles, to see if they can be used as highly sensitive sensors in medical an industrial applications.

Microbubbles are specially-coated bubbles which are designed primarily to enhance ultrasound pulse-echo imagaing.  Their use significantly enhances sound echoes, thereby improving detection accuracy, and therefore diagnosis of 'difficult' cancers (e.g. liver, prostate).

Microbubbles (and specially designed ultrasonic fields) are being studied worldwide as possible vehicles for drug and gene delivery.  They promise to play a crucial role in fighting Alzheimer's disease, or cancers in which the use of chemotherapy is deemed too risky to the patient, and thus a targeted therapy is more effective.

NPL's work in this area is developing the measurement building blocks, to exploit the sensitivity of microbubbles to local changes in their environment, so extending their effectiveness in medical applications and beyond.

For more information about this project contact Phil Jones at UCL, or Gianluca Memoli at NPL.

UCL sp2 Carbon Group

Phil is giving a talk to the UCL sp2 Carbon Group on 'Optical Trapping of Carbon Nanomaterials'

This talk will give a brief overview of our experimants on optical tweezers for trapping and maniplation of carbon nanomaterials, including nanotubes and graphene flakes.  It will start with a description of
the experimental techniques of opical trapping and back focal plane interferometry for paricle tracking, then present results on trapping, tracking and the analysis of Brownian motion of trapped carbon nanotube bundles and graphene flakes, including centre-of-mass and angluar fluctuations and driven rotations, and combined optical tweezers and Raman spectroscopy.


References:
O. M. Maragò, F. Bonaccorso, R. Saija, G. Privitera, P. G. Gucciardi, M. A. Iatì, G. Calogero, P. H. Jones, F. Borghese, P. Denti, V. Nicolosi & A. C. Ferrari. 'Brownian motion of graphene', ACS Nano 4 7515-7523 (2010)

O. M. Maragò, R. Saija, F. Borghese, P. Denti, P. H. Jones, E. Messina, G. Compagnini, V. Amendola, M. Meneghetti, M. A. Iatì, and P. G. Gucciardi.  'Plasmon-enhanced optical trapping of metal nanoparticles: force calculations and light-driven rotations of nanoaggregates', Proc. SPIE Vol. 7762, 77622Z (2010)

O. M. Maragò, P. G. Gucciardi and P. H. Jones.  'Photonic Force Microscopy: from femtonewton force sensing to ultra-sensitive spectroscopy', in Scanning Probe Microscopy in Nanoscience and Nanotechnology 1 (Springer) B. Bushan (Ed.) (2010)

P. H. Jones, F. Palmisano, F. Bonaccorso, P. G. Gucciardi, G. Calogero, A. C. Ferrari & O. M. Maragò.  'Rotation detection in light-driven nanorotors',  ACS Nano 3 3077-3084 (2009)

O. M. Maragò, P. H. Jones and A. C. Ferrari. 'A light touch on nanotubes: femtonewton force sensing and nanometric spatial resolution', SPIE newsroom, doi 10.1117/2.1200901.1475 (2009)

O. M. Maragò, P. H. Jones, F. Bonaccorso, V. Scardaci, P. G. Gucciardi, A. Rozhin, and A. C. Ferrari.  'Femtonewton Force Sensing with Optically Trapped Nanotubes', Nano Letters 8 3211-3216 (2008)

O. M. Maragò, P. G. Gucciardi, F. Bonaccorso, G. Calogero, V. Scardaci, A. Rozhin, A. C. Ferrari, P. H. Jones, R. Saija, F. Borghese, P. Denti & M. A. Iatì.  'Optical trapping of carbon nanotubes’, Physica E 40 2347-2351 (2008)

Optical Techniques in Biological Physics Meeting

The Biological Physics Group of the Department of Physics and Astronomy is hosting a half-day meeting on Thursday 17 February, on the subject of 'Optical Techniques in Biological Physics'.  The meeting brings together researchers from the physical and life sciences with an interest in optical techniques (imaging, spectroscopy, optical traps, etc) for a series of short talks and discussions on opportunities for future interdisciplinary work.  The programme for the day is:

2.00 Introduction (Phil Jones)
2.10 Clare Elwell (Medical Physics & Bioengineering) The use of near infra-red spectroscopy to measure tissue oxygenation, haemodynamics and metabolism
2.40 Angus Bain (Physics) Time-resolved fluorescence studes of biomolecular structure, interactions & dynamics
3.10 Angus Silver (NPP) The acousto-optics lens two-photon microscope and its application to neuroscience
3.40 Tea break
4.00 Chris Thrasivoulou (Cell & Developmental Biology) title tbc
4.30 Guillaume Charras (LCN) Imaging challenges in molecular cell biology
5.00 Open discussions

Jaesuk Hwang seminar

Jaesuk Hwang (Imperial College) is visiting and giving today's AMOPP seminar on 'Quantum nanophotonics with single molecules'.

Abstract:  A new type of atom-photon interface is proposed that can be used as a resource for processing quantum information. Individual organic dye molecules will be deposited close to optical waveguides on a photonic chip.

At cryogenic temperature, the molecules act as simple two-level atoms with a strong electric dipole transition.  They can be individually addressed and they remain trapped indefinitely in the solidified solvent. We demonstrated that a single molecule can obscure a substantial part of the light in a beam whose cross section is comparable to the scattering cross section of the molecule [i].  In such a beam, we showed that the molecule behaves as a two-level quantum emitter whose nonlinear response is appreciable even at very low light intensity.  This was seen through the appearance of Mollow sidebands in the fluorescence spectrum of the molecule.  The relative merits of absorption and fluorescence as a method of detecting single molecules were discussed in ref [ii]. In another proof of the large dipolar coupling we were able to observe Rabi flopping of the two-level molecule in weak light pulses, where only a few hundred photons were enough to generate a p-pulse [iii]. Most recently, we showed that the single molecule can act as an absorber whose absorption coefficient can be manipulated by a control laser and can also be turned into gain when the population of the molecule is inverted [iv].  All-optical nonlinear operation at the single emitter level has been deemed exceptionally challenging and only been considered in high-finesse microcavities. Here, we demonstrate that such operation is possible with single molecules with a propagating laser beams and discuss the possibility of building a quantum network on an optical waveguide chip.

 At cryogenic temperature, the molecules act as simple two-level atoms with a strong electric dipole transition.  They can be individually addressed and they remain trapped indefinitely in the solidified solvent. We demonstrated that a single molecule can obscure a substantial part of the light in a beam whose cross section is comparable to the scattering cross section of the molecule [i].  In such a beam, we showed that the molecule behaves as a two-level quantum emitter whose nonlinear response is appreciable even at very low light intensity.  This was seen through the appearance of Mollow sidebands in the fluorescence spectrum of the molecule.  The relative merits of absorption and fluorescence as a method of detecting single molecules were discussed in ref [ii]. In another proof of the large dipolar coupling we were able to observe Rabi flopping of the two-level molecule in weak light pulses, where only a few hundred photons were enough to generate a p-pulse [iii]. Most recently, we showed that the single molecule can act as an absorber whose absorption coefficient can be manipulated by a control laser and can also be turned into gain when the population of the molecule is inverted [iv].  All-optical nonlinear operation at the single emitter level has been deemed exceptionally challenging and only been considered in high-finesse microcavities. Here, we demonstrate that such operation is possible with single molecules with a propagating laser beams and discuss the possibility of building a quantum network on an optical waveguide chip.

[i] G. Wrigge, I. Gerhardt, J. Hwang, G. Zumofen, V. Sandoghdar, Nature Physics 4, 60 (2008).

[ii] G. Wrigge, J. Hwang, I. Gerhardt, G. Zumofen, V. Sandoghdar, Opt. Express 16, 17358 (2008).

[iii] I. Gerhardt, G. Wrigge, G. Zumofen, J. Hwang, A. Renn, V. Sandoghdar, Phys. Rev. A. 79 011402(R) (2009).

[iv] J. Hwang, M. Pototschnig, R. Lettow, G. Zumofen, A. Renn, S. Goetzinger, V. Sandoghdar, Nature 76 460 (2009).

AMOP Physics Open Day

Today is the AMOP Physics Group Open Day for students interested in studying for a PhD.

Programme:

12:30-13.00 Introductory talk by Peter Barker (Room E7, Physics Dept)
13:00-14:00 Buffet Lunch and theory group posters
14:00-16:00 Lab tours 

Visit to NanoSoft Lab, IPCF-CNR (Messina)

This week Susan and Marios are visiting the NanoSoft Lab at IPCF-CNR (Messina) where they are working with Dr Onofrio Marago.  This visit is part of our long-running collaboration with Dr Marago, and is funded by the Royal Society via an International Joint Project.

Gerard Milburn Seminar

Prof Gerard Milburn (University of Queensland) is giving an AMOPP seminar on Quantum measurement and control of optomechanical systems.

Abstract: The emerging field of quantum optomechanics combines quantum optics and new fabrication techniques to control the quantum state of macroscopic mechanical resonators. This now provides a new approach for controlling the mutual interaction between light and mesoscopic structures, which is one of the eminent goals in quantum information science and of importance for fundamental experiments at the quantum-classical boundary. I will give an overview of this new field and discuss some specific models. These include a scheme to conditionally prepare a macroscopic mechanical resonator in an energy eigenstate by measurement, single photon optomechanics, and quantum entanglement in optomechanical networks

David McGloin Visit and Seminar

David McGloin (Dundee University) is visiting and giving the AMOPP/BioP seminar on Optical manipulation of droplets: aerosols and hydrosomes.

Abstract: In this talk I will discuss work in which my group has developed techniques to optical manipulate liquid droplets in both the air (aerosols) and in another liquid phase (hydrosomes). I will look at hope the optical manipulation of airborne droplets is subtly different from the trapping of particles in liquids in that one can access underdamped particle dynamics in contrast to the conventional heavily overdamped optical tweezers. I will touch on different technqiues for sizing such particles and how droplet composition can be determined using enhanced spectroscopic methods. In addition I will also touch on how optical fields can also be used to manipulate lqiuid droplets in an oil phase, both through direct optical forces and through thermal manipulation, and how this could lead to interesting ways to develop new forms of biological well plates.