23/02/16 – Quantum Fluids of Light
Univ. Paris Diderot, France
I will review recent theoretical and experimental advances in the manybody physics of light , including superfluid-like optical propagation effects. I will also give an overview of the recent frontier concerning strong photon-photon interactions and
non-equilibrium strongly correlated phases of light, which can be achieved in arrays of coupled nonlinear resonators (e.g., semiconductor photonic microcavities, superconducting nonlinear quantum resonators).
 I. Carusotto, C. Ciuti, Rev. Mod. Phys. 85, 299 (2013).
08/03/16 – The Quest for "Perfect" Diamond Qubits
University of Ulm
Colour centres in diamond are attractive architectures for qubits and spin-photon interfaces, but the currently available candidates are not perfect. The famous nitrogen vacancy (NV) centre fluorescence spectrum exhibits a number of undesirable characteristics
including a strong phonon sideband and, typically, spectral diffusion of the zero-phonon line (ZPL). More recently the related silicon vacancy (SiV) centre has been shown to have exceptional optical properties, but a fundamentally limited spin coherence time of only 40 ns. What’s needed is a "smart
search" for novel diamond qubits, hopefully pointing towards a future where colour centres can be "engineered" for specific applications.
The brand-new germanium vacancy centre will be presented as an example of this process. There is a tantalising possibility that germanium vacancies could combine the excellent spin coherence properties of NV with the superb spectral properties of SiV, leading to an almost perfect diamond qubit.
12/04/16 – Gigahertz Laser Frequency Combs
A modelocked laser can support not only very short pulses but at the same time very precise frequency metrology for the most accurate clocks. These ultrafast – or ultra-short pulse – lasers are dramatically impacting many areas of photonics, from basic science
to industrial manufacturing and biomedicine. The design and performance of the lasers behind these applications is critical for new discoveries, creating new applications and opening new market opportunities. Modelocked lasers produce a frequency comb for which the frequency spacing (i.e. the pulse repetition
rate) has been stabilized in the 1980’s achieving close to quantum-noise limited performance with diode-pumped solid-state lasers. However the stabilization of the frequency comb offset (i.e. the carrier envelope offset (CEO) frequency) remained a challenge and only has become possible 1999. Since
then the field of optical frequency combs has evolved very quickly, and current applications range from high-precision spectroscopy over frequency metrology to ultra-high-speed optical communication. Many of these applications are based not only on one, but on two frequency combs such as dual-comb spectroscopy,
asynchronous optical sampling, pump probe measurements and fiber Bragg grating sensing.
This talk will review our progress on gigahertz frequency combs based on modelocked semiconductor and solid-state lasers, stabilized by external silicon nitride waveguides or PCFs with an f-to-2f interferometer. Novel dual comb modelocked lasers are presented where an intracavity birefringent crystal
in a MIXSEL is used for polarization-duplexing to obtain simultaneous emission of two modelocked beams from the same linear cavity sharing all components. Initially surprising was the observation that the cavity length adjustments to stabilize one polarization did not significantly affect the pulse repetition
rate of the other.
19/04/16 – Recent Advances in the Physics and Applications of Metamaterials
Australian National University
Metamaterials, artificial electromagnetic media that are structured on the subwavelength scale, were initially suggested for the negative-index media, and later became a paradigm for engineering electromagnetic space and controlling propagation of
waves. The research agenda has shifted towards achieving tunable, switchable, nonlinear and sensing functionalities of metamaterials, and also shaped around a new platform of two-dimensional metamaterials, or metasurfaces. A few years ago we put forward the concept of metadevices defined as photonic
devices having unique and useful functionalities realized by structuring functional matter on the subwavelength scale.
More importantly, rapid progress in the fields of plasmonics and metamaterials is driven by their ability to enhance near-field effects with subwavelength localization of light, and a majority of such effects is usually associated with metallic nanoscale structures such as « meta-atoms »
and « meta-molecules ». Recently, we observe the emergence of a new branch of nanophotonics aiming at the manipulation of strong optically-induced electric and magnetic Mie-type resonances in dielectric and semiconductor nanostructures with high refractive index. Unique advantages of dielectric
resonant nanostructures over their metallic counterparts are low dissipative losses and the enhancement of both electric and magnetic fields that provide competitive alternatives for metal-based plasmonic structures including nanoantennas, nanoparticle sensors, and metasurfaces. Here, we review this
new emerging field of nanophotonics and metamaterials and demonstrate that Mie-type resonances in dielectric nanoparticles and subwavelength-patterned dielectric structures can be exploited to boost performance of many nanophotonic metadevices. In addition, the coexistence of strong electric and magnetic
resonances and resonant enhancement of magnetic field in dielectric nanoparticles bring new physics and entirely novel functionalities to simple geometries not much explored in plasmonic structures especially in the nonlinear regime.
This talk will summarize research on electromagnetic metamaterials and metadevices with different functionalities including the property of hyperbolic dispersion and all-dielectric nanophotonics.
26/04/16 – In the spirit of Joe Moyal: Phase-space physics – diabolism, whorls and tendrils, wignereal disease, superoscillations…
University of Bristol
At the heart of conical refraction – Hamilton’s first physical prediction based on phase space – is a conical singularity: a diabolical point. Geometrical objects characterising the classical evolution of families of orbits are phase-space
whorls (near stable fixed points) and tendrils (near unstable fixed points). The discordance between chaotic classical evolution and the corresponding quantum evolutions can be understood by the spreading of Wigner functions in phase space: slower as Planck’s constant increases. Notwithstanding
the uncertainty principle, five equivalent local momenta can be associated with a quantum state, often describing spatial variations much faster than the Fourier content of the state might suggest.
03/05/16 – Structure-Function Relationships in Complex Macromolecular Assemblies
Victor Chang Cardiac Research Institute
The microscopic world of our cells is filled with complex molecular assemblies that dynamically move and interact to perform their function. This can range from molecular motors spinning thousands of times a minute, to large cages that massage
molecules into their correct shape. Here we will discuss our recent work on two such proteins; ATP synthase, a multi subunit generator responsible for converting most of the chemical energy in the cell, and chaperonins, enormous complexes that use chemical energy to refold proteins.
24/05/16 – Creating a Sense of Space – A Hitchhiker’s Guide to Spatial Hearing
Most sounds have an ‘out-thereness’ - they appear to originate from somewhere, and are usually attributed to the specific source, or sources, from which they originate. Nevertheless, unlike vision or touch, for example, the sensory end organs in
the sense of hearing – the cochlea in the inner ear - contain no specialized receptors for determining the location of sound sources. To this end, cues to the location of a source must be computed from information that, of itself, is not spatial. Beyond this, our perception of the acoustic space
in which we reside is also critical to our ‘connectedness’ to that space.
Starting with the work of Lord Rayleigh, this seminar will demonstrate how our understanding of spatial hearing has developed alongside the development of techniques used to assess brain function. With precision in the order of a few tens of microseconds, sensitivity to auditory spatial cues challenges
our understanding of how technologies such as cochlear implants – devices that replace the function of the inner ear entirely - can be used to create a sense of space in individuals for whom the concept of sound is truly alien.
31/05/16 – Keeping Astronomers (And Others) In The Dark
Australian Astronomical Observatory
One of the more notable outcomes of last year's International Year of Light was an increased awareness of darkness. With light pollution damaging the night skies of all the world's cities, there is a growing call for better-designed outdoor lighting
to improve the nocturnal environment and avoid wasted energy. This talk shows how today's technology makes that eminently attainable. It also looks closely at threats to the night sky of Siding Spring Observatory, where a pristine environment is of paramount importance. Reclaiming the night sky is not
just for astronomers and nocturnal animal species, however - it is to the benefit of everyone.
14/06/16 – Imaging with Nanodiamonds
University of Sydney
Nanodiamonds attract a lot of interest for quantum information technology, metrological sensors, and more recently as a probe of biological environments. Their easily adaptable carbon surface and non-toxic nature have allowed the use of dimaonds as vectors
for therapeutic drug delivery, and as optical sensors of subcellular processes. However, a means of non-invasively imaging nanodiamonds in-vivo is still lacking. In this talk I will present various modalities to approach imaging of nanodiamonds in a biological environment.
21/06/16 – ASKAP, WALLABY and HI in Galaxies
I will provide an update on the Australian SKA Pathfinder (ASKAP), highlight the planned surveys, including my ASKAP HI All Sky Survey (known as WALLABY), and outline our plans for Early Science with the first 12 ASKAP antennas. Our novel Phased-Array Feeds (PAFs) have a
field-of-view of 30 square degrees, making ASKAP a fast 21-cm survey machine. WALLABY is expected to detect more than 500,000 galaxies and will tackle a large range of science projects. I will also highlight our data visualisation work of nearby galaxies and galaxy groups, with some focus on large and
warped galaxy HI disks.
28/06/16 – Structure and Dynamics at the Centre of the Milky Way
The Central Molecular Zone (CMZ) of our Milky Way Galaxy contains 80% of all dense gas in the Galaxy, but holds only about 5% of current star formation. It is hotter, denser and more turbulent than anywhere else in the Galaxy - conditions analogous to distant
galaxies used to estimate cosmic star formation rates. Yet we do not understand the star formation in the CMZ! I will present recent models of the CMZ to explain its unusual star formation properties. I will also introduce a way to make a 3 dimensional model of the CMZ with the hope that this can help
us understand how star formation proceeds under extreme circumstances.