PHOTONICS GROUP OPEN DAY AND LAB TOURS Wednesday 30th January 2013, Room 630, Blackett Laboratory Introduction to MRes in Photonics: 2.00pm Introduction to PhDs in Photonics: 2.30pm Refreshments: 4.30pm-5.30pm Thank you for your interest in the Photonics Group. This handout is designed to give a short summary of the MSc and PhD opportunities within the group and to provide links to other relevant information. For more information please visit our website http://www3.imperial.ac.uk/photonics or contact [email protected] PHD STUDENTSHIPS IN THE PHOTONICS GROUP Each year the Photonics Group recruits up to ~10 research students for a variety of different projects, supported by a range of sponsors. In general, we expect our research students to undertake a four year MRes+PhD programme. The MRes course runs for one year and entails a term of lectures and practical work in optics and photonics (alongside the MSc in Optics and Photonics) followed by a 9 month MRes project with the prospective PhD supervisors as well as selected specialist lectures. Students are required to pass the MRes degree course before being eligible to proceed to the PhD. Progression to the PhD is expected but not automatic. Students are then expected to complete their PhD research and to submit their theses within three years. If applicants already have an MSc or MRes degree in an optics-related discipline, they may be exempted from the requirement to study for the MRes degree in Photonics. Funding for research studentships Broadly, most of our PhD students are supported either by a centrally allocated studentship from our EPSRC Doctoral Training Account (DTA), by a Research Council, DTI or EU project studentship (associated with a specific research grant), by a scholarship designed for overseas students (usually from the student’s own government), by industrial sponsorship or by private funding. Note that self-funded and externally funded students are also required to study for the MRes+PhD degrees where appropriate and should budget accordingly. More information on scholarships and awards can be found on our website. When to apply MSc in Optics and Photonics We recommend that interested applicants apply to study for a PhD with us as early as possible in the academic year because we receive many applications from final year undergraduates or MSc students aiming to start in the coming October. We note, however, that opportunities can arise throughout the year and encourage potential applicants to contact us as soon as they decide they are interested in joining us. If you are interested in a research career in optics and photonics and are not ready or interested in studying for a PhD, you may also wish to apply for a place on our MRes or MSc courses. The MSc in Optics and Photonics provides an excellent training for the optics and photonics industry and MSc graduates may also go on to study for a PhD in Optics and Photonics. Opportunities for the coming year All academic staff members of the Photonics Group aim to recruit PhD students for the next academic year. We normally award EPSRC DTA studentships to start in October, although it is sometimes possible to start earlier. Please see our website for a list of specific PhD projects for which we are now recruiting. If you are interested in an area not covered by this list of possible projects, please do talk to the appropriate academic supervisor, who may be able to advise you of other opportunities. Eligibility for PhD research within the Photonics Group We welcome applications for PhD research from students around the world. Applicants should have, or be expecting, a First class honours degree, or a good Upper-Second, in physics or engineering and be strongly motivated to undertake challenging, cutting-edge research in photonics. We believe that our research students' achievements are, and should be, competitive with those of the best research universities in the world. This implies a world-class level of commitment and professionalism from our staff and our students. We place significant emphasis on teamwork and effective communication. PHOTONICS GROUP OPEN DAY TIMETABLE WEDNESDAY JANUARY 30TH, 2013 14.00 – 14.30 Introduction to MSc in Optics & Photonics/MRes in Photonics by Kenny Weir and Andrew Williamson in Room 630, Blackett Laboratory 14.30 - 15.00 Introduction to studying for a PhD in Photonics, in Room 630, Blackett Laboratory 15.00 - 16.30 Laboratory tours 15.00 - 15.20 Theoretical Projects Talk by Martin McCall, in Room 613, Blackett Laboratory. Attendees to join lab tours following talk 16.30 - 17.30 Drinks reception and chance to meet current PhD students and research staff in Room 630, Blackett Laboratory Photonics Group Research Our broad research themes are fibre and laser optics, electromagnetic theory, imaging technology and applications and biophotonics. Current fibre/laser projects include compact and high power fibre and solid-state laser technology, including broadly tunable supercontinuum sources, ultrafast fibre lasers, amplifiers and nonlinear optics. Theoretical projects include rigorous electromagnetic theory (FE, FDTD, volume integral methods) applied to imaging, optical storage and polarisation studies, chiral media, Bragg structures and photonic crystals. Our imaging projects focus on adaptive optics applied to astronomy, microscopy and ophthalmic imaging and optical molecular imaging, including multidimensional fluorescence imaging implemented in microscopy, endoscopy and tomography systems, applied to tissue diagnosis, molecular biology and drug discovery. Most of our projects are interdisciplinary and we work closely with industry. http://www3.imperial.ac.uk/photonics Optical fibre laser technology S.V. Popov and J.R. Taylor Over the past year, the emphasis of the group’s research has redirected from high average power supercontinuum sources towards short pulse, fibre-based, wavelength specific sources. Although all-fibre high average power supercontinuum sources, as originally developed by the group, are commercially successful and finding diverse applications, they are frequently spectrally filtered to provide radiation in only a single or a few wavelength bands. Apart from being an inefficient means of generating such radiation, such sources provide limited (albeit relatively impressive) average spectral power densities of a few tens of milliwatts per nanometre that constrain the range of potential applications. It may be more efficient in many circumstances to employ MOPFA (master oscillator power fibre amplifier) configurations, which are themselves the basis of many supercontinuum pump sources, to directly provide the pump radiation for specific nonlinear optical processes as a means to achieve high (watts) average powers at specific wavelengths. To this end we have investigated both parametric and Raman generation, both in conventional and photonic crystal fibres, as potential means to high power spectrally versatile radiation. For the first approach we have developed a parametric source synchronously pumped by a Yb based MOPFA at 1 m in the long pulse picosecond regime and achieved fibre dependent phase matched generation to the red. For the latter approach, we have developed passively mode locked Raman lasers utilizing both carbon nanotubes and graphene as nonlinear (saturable) absorbers. Graphene provides a tuning range of operation from 400 nm to 2000 nm and, coupled with fibre based Raman gain, represents a route to a universal ultrashort pulse source that is limited only by the wavelength of the pump laser. This pump can itself be a c.w. tunable fibre Raman laser - thus allowing almost unlimited wavelength ultrashort short pulse coverage. Initial investigations have concentrated in the mid infrared, employing normally dispersive cavities to produce long, linearly chirped picosecond pulses that can be temporally compressed using anomalously dispersive fibres or grating pairs. Operation in the visible spectral region is currently under investigation. One disadvantage of current carbon nanotubes and graphene absorbers is the potential of optically damaging the polymer host in which they are held. We are currently investigating the application of ionically doped glass hosts, which should provide absorbers that are less susceptible to absorptive damage. We are also investigating quantum dots in glass as alternative saturable absorbers for fibre lasers. For spectral coverage in the 1100 nm to 1500 nm range, we are investigating Bismuth doped silica fibres to provide a broadband gain medium, although it offers a relatively modest efficiency compared to the more common rare earth active ions. For optical telecommunications we have demonstrated the first picosecond amplification at high bit rates (~20GBit/s), indicating the potential of bismuth to provide much-needed bandwidth extension. For high power applications, we are also developing Tm-doped fibre chirped pulse amplifier schemes at 2 m and large mode area passively mode-locked femtosecond Yb fibre lasers with proposed power scaling to the 30-50 W average power regime. Second harmonic generation of Bi-doped fibre laser at 589 nm Fibre laser sources for medical applications S. V. Popov In collaboration with industrial integrators and the Department of Surgery at Imperial College London, Imperial NHS Trust and the Department of Computing, we are developing and implementing trials of wavelength-specific laserbased devices for urological, Ear Nose Throat, and robotically assisted surgery. Developing spectrally versatile all-fibre laser technology using doped, Raman or frequency doubled fibre lasers allows us to build single or multiple wavelength fibre laser systems of tens of watts average power for therapeutic medical applications. By adjusting the irradiation wavelength we can optimise the interaction with the tissue, maximizing the tissue removal or coagulation while minimizing the surrounding thermally affected zones and hence potentially reducing pain effects and rehabilitation time. Furthermore, optical fibre based instruments have the inherent capability to deliver light to a desired location and to operate metal-free in magnetic field environment like MRI. Bismuth based MOPFAs have also been developed and frequency doubled to generate tunable radiation in the 590 nm regime for skin pigmentation treatment and ophthalmic coagulation However, to be competitive it will be essential to improve the efficiency of Bi based devices through studies of the photophysics of the active ions. Spectral range of tissue chromophores with therapeutic laser wavelengths indicated (left), together with laser surgical tools (top right) and compact fibre laser (bottom right) Nonlinear Optics and Laser Technology G. Thomas and M. Damzen Lasers have had a profound impact on society by enabling technologies in manufacturing, telecommunications, medical and sensing applications to name a few. We are developing a range of cutting-edge all-solid-state lasers and nonlinear optical technologies that exploit novel basic science techniques but are focused on solving next-generation technological problems ranging from precision laser manufacturing (e.g. processing of solar cells) to satellite-based remote sensing (e.g. Earth Observation for weather prediction and climate change science). A key feature of our research is the radical new diode-pumped micro-slab laser technology pioneered in our laboratory, demonstrating a unique combination of performance, including World’s highest power diode-pumped compact size, ultra-high efficiency, high power, excellent beam Alexandrite Laser, with high pulse energy quality and controlled pulse delivery. The micro-slab technology (>23mJ @ 100Hz) developed as a source for has been commercialized through spin-out company Midaz Lasers next generation satellite-based remote sensing. Ltd, founded by Prof. Damzen in 2006, which has engineered and delivered lasers and amplifiers world-wide to enable next generation manufacturing. It forms a collaborative link between our basic research work and the route to commercial markets where appropriate. In collaboration with Midaz, we have recently developed the world’s highest power diode-pumped Alexandrite laser. We have developed this highly efficient, broadly tunable laser for the European Space Agency (ESA) for next-generation satellite-based remote sensing, but it also has potential as an amplifier technology for high energy femtosecond lasers for cuttingedge light-matter interaction science. Our group is also a world-leader in self-organising lasers that can “intelligently” self-correct their operation by exploit dynamic (nonlinear optical) holography inside the laser. We have recently demonstrated how multiple self-organising lasers can be made to “communicate” and organise themselves into a single coherent “super-mode” laser output, as a route to high power scaling of lasers. Space-time Cloaking A. Favaro, P. Kinsler, M. McCall We have extended the idea of cloaking objects in space to hiding events in space-time. Whereas a spatial electromagnetic cloak is designed to caress light around an object as shown in figure (a), rendering it invisible to a distant observer, in the new scheme one spatial variable is replaced by time. Instead of deviating light rays around an object, different portions of a ray are sped up and slowed down such that certain events are never illuminated, as represented in figure (b). On reversing the process, the illuminating light is restored to its original uniform condition so that a distant observer will never Representations of (a) spatial cloak and (b) space-time cloak in which the which the object is never illuminated by the evolving light distribution such that the observer sees an “undisturbed” uniform light sheet suspect the occurrence of the un-illuminated events. The design arose from manipulating the covariant form of Maxwell's equations under coordinate deformations, which, for the event cloak, must embrace time as well as space. Reinterpreting such deformations as a dynamic change of material parameters, a hole in space-time can be actualised in a physical medium. The best event cloak solution turned out to be a design in which the material is engineered to appear as though it is moving. When this effective speed varies for different points on the ray, as well as varying with time, the prescribed light-speed modulation can be achieved. Although such a design is beyond current metamaterials technology, we proposed a simple event cloak using programmable nonlinearity in optical fibers and recently the first such experimental spacetime cloak has just been demonstrated in the laboratory at Cornell University. The “event cloak” concept has opened up a significant new cloaking paradigm that is only just beginning to be explored. It was hailed by a panel of journalists as the third most significant breakthrough in Physics for 2011, and was selected for feature in the OSA’s ‘Highlights’ for 2011. Electromagnetic Imaging with Applications to Sensing and Microscopy C.A. Macias Romero, M.R. Foreman, P. Török Our research is centred on applications of high numerical aperture, electromagnetic imaging. A key strength is ultra high-resolution micropolarimetry, with which it is possible to determine the polarisation properties of samples such as 2-D and 3D metamaterials and micromagnetic structures with extreme accuracy. The example in the figure shows the measured polarisation map of the diattenuation exhibited by a silver nanowire when illuminated with 405 nm radiation. A more prosaic application of micropolarimetry is optical data storage where we aim to increase the maximum information content per unit area on an optical disk using an approach we describe as Multiplexed Optical Data Storage (MODS) that encodes more than a single bit of information into a single pit. We are also exploring the optical nonlinearity of materials with a view to increasing the numerical aperture of the lens. Polarisation map of the diattenuation exhibited by a silver nanowire A significant new research effort is focused on sensing and detection of bacteria at low concentration in their natural environment. We have developed a solution for detecting bacteria in the order of minutes without the need for incubation. We are also working in collaboration with the Institute of Food Research to study pathogenic bacteria by means of localisation microscopy and dielectrophoretic trapping. With C. Paterson we are developing confocal Brillouin scattering microscopy to measure the 3-D micromechanical properties of bacteria and biofilms, as well as polymers where time dependent polymerisation can be mapped. Programmable Light M. Neil We are working to manipulate light in a programmable fashion for applications in microscopy, metrology and the life sciences. We continue to develop the application of spatial light modulators, using this technology to define arbitrary wave-front shapes for metrology of large mirrors, to control the point spread function in microscope systems for polarisation and super-resolution imaging and for optical trapping. As part of the Single Cell Proteomics project at Imperial, we are using optically trapped and biochemically functionalised oil droplets - Smart Droplet Programmable interferometer map of a mirror substrate Microtools - to manipulate and probe biological cells. Research in this area has recently been extended with EPSRC grants looking at protein oxidation (the “Proxomics” project) nano-fluidics and fabrication (the “Optonanofluidics” project) within the newly established Institute of Chemical Biology at Imperial. We continue to develop bio-imaging applications exploiting Smart Droplet manipulated with optical programmable light. We have recently started a collaborative EU tweezer to trypsinize cell funded project “OptoNeuro” using micro-led array technology for opto-genetics, for which we are developing micro- and macro-optics systems to project light onto both cell cultures and into the eye for prosthetic sight applications. In conjunction with Aurox Ltd we are working on structured illumination projection systems for wide-field optical sectioning microscopy. Multidimensional fluorescence imaging across the scales Y. Alexandrov, S. Coda, G. Kennedy, S. Kumar, M. Lenz, A. Margineanu, I. Munro, R. Patalay, C. Talbot, C. Dunsby, J. McGinty, M. Neil, P. French Our overarching mission is to create new opportunities for scientific discoveries, particularly in biomedicine, by developing and applying ultrafast and tunable laser and photonics technology to novel imaging and metrology applications. We mainly work in multidisciplinary collaborations with bioengineering, biology, chemistry, medicine and physics, developing and applying multidimensional fluorescence imaging (MDFI) technology, with a particular emphasis on fluorescence lifetime imaging (FLIM), for clinical diagnosis, molecular biology and drug discovery. Our FLIM technology provides molecular contrast of different chemical species and different fluorophore environments utilizing both one and two photon excitation and implemented in instruments ranging from multidimensional fluorometers for in vitro solution-based measurements to super-resolved microscopy, high speed and automated imaging of live cells, tomographic imaging in live disease models and in vivo measurements in patients for clinical diagnosis. 3-D STED image of cortical actin and FLIM STED of actin & Arp protein at immunological synapse between cells A key strength is our high-speed wide-field time-gated FLIM technology that is being applied to clinical endoscopy and multiwell OPT OPTimage imageofofjuvenile juvenilezebrafish zebrafishwith withtumour plate reader systems for High Content Analysis, as well as to intumour red in red microscopy of cell biology, disease states in tissue and reactions in microfluidic devices. Where appropriate, we combine optical sectioning and FLIM with multispectral or hyperspectral imaging (realizing 5-D fluorescence imaging) or with polarization resolution to image rotational diffusion dynamics. The latter may be used to obtain 3-D images of ligand binding or viscosity distributions. We have recently developed a super-resolution FLIM microscope system based on STimulated Emission Depletion (STED) microscopy, which allows sub-diffraction limited multilabel images to be obtained in a scanning confocal microscope. As well as studying disease mechanisms in cell biology, we are also applying STED microscopy to study nitrogen defects in diamond. To study cell signalling processes we apply FLIM and MDFI techniques to image protein interactions using FRET, including in automated multiwell plate readers, and recently demonstrated multiplexed FRET – simultaneously reading out two different protein interactions. For drug discovery and for biological research, there is an increasing trend to translate live cell imaging experiments and assays from monolayers of cells in culture to more physiological realistic contexts, including live disease models. To this end we have developed the first FLIM-optical projection tomography system, which we have demonstrated for imaging live disease models such as zebrafish. We have also developed a novel high speed 3D fluorescence imaging system called Oblique Plane Microscopy (OPM) enabling dynamic events to be studied in 3D at video rate. We also believe there is significant scope for translating our imaging capabilities to clinical application for improved diagnosis, intervention and drug discovery. For clinical studies we have deployed a novel multiphoton microscope at Hammersmith Hospital to exploit label-free autofluorescence contrast in tissue for diagnosis of skin cancer, of which an example recorded in vivo is shown in the figure. We are also developing FLIM endoscopes utilising both wide-field time-gated imaging and laser scanning microconfocal endoscopes. We have recently started our first in vivo trial of a fibre-optic probe based multidimensional fluorescence spectroscopy system for use in the gastrointestinal tract and are developing novel illumination strategies for clinical endoscopy and surgical procedures including a new approach to laser scanning endoscopy that provides unprecedented miniaturisation with no distal moving parts. Clinical multiphoton FLIM microscope with optically section FLIM image Adaptive Optics and Retinal Imaging D. Lara, C. Paterson Adaptive optics initially arose to solve the problem facing astronomers of how to overcome the severe limitation on imaging resolution caused by the effects of random, dynamic aberrations arising from atmospheric turbulence. In our research we are developing the technology and applying it to other situations such as biomedical microscopy and ophthalmic imaging. In the case of retinal imaging, aberrations include dynamic contributions from the tear-film dynamics as well as the aberrations from the cornea and lens. Correcting aberrations using adaptive optics makes it possible to image individual photoreceptors at the fovea and to obtain detailed images of the cardiovascular system at the front of the retina. . The Confocal scanning laser ophthalmoscope principle is the same as for astronomy: the dynamic aberrated image of the photoreceptor mosaic of the wavefronts are measured using a wavefront sensor and corrected in human retina real time using an active deformable mirror. We are applying information theoretical approaches to improve the efficiency of wavefront sensing for this and other applications. We have also been applying estimation techniques from adaptive optics to the analysis of retinal images which in collaboration with ophthalmologists at City are helping in the early diagnosis of retinal diseases. We are now extending our high resolution retinal imaging to include full polarisation properties of the retina, using Mueller matrix imaging. This will enable us to image structures not possible with conventional techniques with the hope that this will lead to new understanding of the causes of loss of vision where current treatments are ineffective.