A5028745273- Mechanical and Optical Resonators
- Quantum optics and atomic interactions
- Diamond and Carbon-based Materials Research
- Photonic and Optical Devices
- Atomic and Subatomic Physics Research
- Advanced Frequency and Time Standards
- Advanced Fiber Laser Technologies
- Electronic and Structural Properties of Oxides
- Acoustic Wave Resonator Technologies
- Cold Atom Physics and Bose-Einstein Condensates
- Semiconductor materials and devices
- Quantum Information and Cryptography
- Force Microscopy Techniques and Applications
- Electron Spin Resonance Studies
- Metal and Thin Film Mechanics
- Graphene research and applications
- Magneto-Optical Properties and Applications
- Ga2O3 and related materials
- Quantum and electron transport phenomena
- Particle accelerators and beam dynamics
- Semiconductor Lasers and Optical Devices
- Transition Metal Oxide Nanomaterials
- Semiconductor materials and interfaces
- Photorefractive and Nonlinear Optics
- ZnO doping and properties
The University of Melbourne
2016-2025
CSIRO Manufacturing
2024-2025
Centre for Quantum Computation and Communication Technology
2018
ARC Centre of Excellence for Engineered Quantum Systems
2011-2016
The University of Western Australia
2008-2016
Western University
2014
The University of Queensland
2011
University of California, Santa Barbara
2011
Using a sub-millimetre sized YIG (Yttrium Iron Garnet) sphere mounted in magnetic field-focusing cavity, we demonstrate an ultra-high cooperativity of $10^5$ between magnon and photon modes at millikelvin temperatures microwave frequencies. The cavity is designed to act as dipole by using novel multiple-post approach, effectively focusing the field within crystal with filling factor 3%. Coupling strength (normal-mode splitting) 2 GHz, (equivalent 76 linewidths or $0.3$ Hz per spin), achieved...
Resonant photon modes of a 5-mm-diameter yttrium iron garnet (YIG) sphere loaded in cylindrical cavity the 10--30-GHz frequency range are characterized as function applied dc magnetic field at millikelvin temperatures. The confined mainly to and exhibited large mode filling factors comparison previous experiments, allowing ultrastrong coupling with magnon spin-wave resonances. largest observed between photons magnons is $2g/2\ensuremath{\pi}=7.11$ GHz for 15.5-GHz mode, corresponding...
Low-loss, high frequency acoustic resonators cooled to millikelvin temperatures are a topic of great interest for application hybrid quantum systems. When 20 mK, we show that resonant phonon modes in bulk wave quartz resonator demonstrate exceptionally low loss (with Q-factors order billions) at frequencies 15.6 and 65.4 MHz, with maximum f · Q product 7.8 × 1016 Hz. Given this result, the Q-factor such devices near ground state can be four orders magnitude better than previously attained....
Progress in the emerging field of engineered quantum systems requires development devices that can act as memories. The realization such by doping solid-state cavities with paramagnetic ions imposes a tradeoff between ion concentration and cavity coherence time. Here, we investigate an alternative approach involving interactions photons naturally occurring impurity ultrapure crystalline microwave exhibiting exceptionally high quality factors. We implement hybrid whispering gallery/electron...
The microwave properties of a crystalline sapphire dielectric whispering gallery mode resonator have been measured at very low excitation strength (E/ℏω≈1) and temperatures (T≈30 mK). measurements were sensitive enough to observe saturation due highly detuned electron spin resonance, which limited the loss tangent material about 2×10−8 13.868 13.259 GHz. Small power dependent frequency shifts also correspond an added magnetic susceptibility order 10−9. This work shows that quantum resonators...
The confinement of high frequency phonons approaching 1 GHz is demonstrated in phonon-trapping acoustic cavities at cryogenic temperatures using a low-coupled network approach. range extended by nearly an order magnitude, with excitation greater than the 200th overtone achieved for first time. Such operation reveals Rayleigh-type phonon scattering losses due to highly diluted lattice impurities and corresponding glasslike behavior, maximum ${Q}_{L}\ifmmode\times\else\texttimes\fi{}f$ product...
3D printing of plastics, ceramics, and metals has existed for several decades revolutionized many areas manufacturing science. Printing metals, in particular, found a number applications fields as diverse customized medical implants, jet engine bearings, rapid prototyping the automotive industry. Although techniques are used they commonly rely on computer controlled melting or sintering metal alloy powder using laser electron beam. The mechanical properties parts produced such way have been...
The p-type surface conductivity of hydrogen-terminated diamond (H-diamond) provides a viable approach toward diamond-based wide-bandgap metal-oxide-semiconductor field-effect transistors (MOSFETs) for high-power and high-frequency electronics. A facile, low-cost, low-temperature method to form gate dielectrics on that also preserves the integrity hydrogen-termination is highly desirable high-performance electronics with process flexibility high yield. In this work, we demonstrate p-channel...
We report strong coupling between an ensemble of N impurity (P1) centres in diamond and microwave photons using a unique double post re-entrant cavity. The cavity is designed so that the magnetic component field spatially separated from electric focused into small volume which sample mounted. novelty structure simultaneously allows high filling factor (38.4\%) low frequencies necessary to interact, at field, with transitions such as those NV$^{-}$ P1 centres. Coupling strength (or...
Indium nitride (InN) has been of significant interest for creating and studying two-dimensional electron gases (2DEG). Herein we demonstrate the formation 2DEGs in ultrathin doped undoped 2D InN nanosheets featuring high carrier mobilities at room temperature. The synthesis is carried out via a two-step liquid metal-based printing method followed by microwave plasma-enhanced nitridation reaction. Ultrathin with thickness ∼2 ± 0.2 nm were isolated over large areas lateral dimensions exceeding...
The use of a transition metal catalyzed thermochemical etching method for improving the carrier transport properties near-surface two-dimensional (2D) hole gas in surface transfer-doped hydrogen-terminated (111) diamond is demonstrated. Using Ni0.8Cr0.2 films deposited and annealed to temperature 900 °C, with up three etch cycles, preferential produces large terraces exceeding 10 μm size microroughness, σRMS2λ, that two orders magnitude lower than pre-etched surface. Magnetotransport...
Employing a sapphire whispering gallery mode resonator, we demonstrate features of the spin-photon interaction in cavities with broken time-reflection symmetry. The symmetry leads to lifting degeneracy between left-handed and right-handed polarized cavity photons, which results an observable gyrotropic effect. In high-$Q$ limit, such situation requires modification Tavis-Cummings Hamiltonian take into account conservation spin angular momentum corresponding selection rules. As result, system...
We report observations of the Schawlow-Townes noise limit in a cryogenic sapphire secondary frequency standard. The effect causes fundamental to stability, and was measured through novel excitation bimodal maser oscillation Whispering Gallery doublet at 12.04 GHz. beat 10 kHz between oscillations enabled sensitive probe for this measurement fractional instability ${10}^{\ensuremath{-}14}{\ensuremath{\tau}}^{\ensuremath{-}1/2}$ with only 0.5 pW output power.
A hydrogen-terminated diamond (H-terminated diamond) surface supports a two-dimensional (2D) p-type conductivity when exposed to the atmosphere, as result of transfer doping process. The formation reliable Ohmic contacts that persist cryogenic temperature is essential for exploration quantum transport in 2D conducting channel. Herein, contact properties Pd on H-terminated have been fully investigated down 4 K using transmission line method measurements. shown form an with linear I–V...
We present new results on a cryogenic solid-state maser frequency standard, which relies the excitation of whispering gallery (WG) modes within doped monocrystalline sapphire resonator (¿-Al <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> ). Included substitutively highest purity HEMEX-grade crystal lattice are Fe <sup xmlns:xlink="http://www.w3.org/1999/xlink">2+</sup> impurities at...
Fe3+ ions in sapphire exhibit an Electron Spin Resonance (ESR) which interacts strongly with high-Q Whispering Gallery (WG) modes at microwave frequencies. We report the first observation of a third-order paramagnetic nonlinear susceptibility such resonator cryogenic temperatures, and demonstration four wave mixing (FWM) using this parametric nonlinearity. This all-microwave nonlinearity is enabling step towards host quantum measurement control applications utilize spins solids.
The development of a new era quantum devices requires an understanding how paramagnetic dopants or impurity spins behave in crystal hosts. Here, we describe spectroscopic technique which uses traditional electron spin resonance (ESR) combined with the measurement large population electromagnetic whispering gallery modes. This allows characterization physical parameters ions at low temperatures. We present measurements two ultrahigh-purity sapphires cooled to 20 mK temperature, and determine...
Hydrogen-terminated diamond possesses a quasi two-dimensional, sub-surface hole accumulation layer with strong and tunable spin-orbit coupling due to surface transfer doping. We report magnetoresistance study of the phase coherent backscattering (weak localization antilocalization) at low temperatures. The response an external magnetic field is highly anisotropic, confirming 2D nature carriers despite short mean free path. By simultaneously applying perpendicular parallel fields, we are able...
We report the study of interactions between cavity photons and paramagnetic Cr$^{3+}$ spins in a ruby (Cr$^{3+}$:Al$_2$O$_3$) Whispering Gallery mode (WGM) resonator. Examining system at microwave frequencies millikelvin temperatures, spin-photon couplings up to 610 MHz or about 5% photon energy are observed impurity high quality factor ($Q > 10^5$) WGM. Large tunability spin-spin interaction allows operation strong coupling regime. The exhibits behaviour not predicted by usual...
Monolayer tungsten diselenide (1L-WSe2) has been widely used for studying emergent physics due to the unique properties of its valence bands. However, electrical transport studies have impeded by lack a reliable method realize Ohmic hole-conducting contacts 1L-WSe2 especially at low carrier densities and temperatures. Here, we report low-temperature p-type contact field-effect transistors (n) below n = 1 × 1012 cm–2 with negligible temperature dependence down lowest measured (10 K). The...
Resonance modes in single crystal sapphire $(\ensuremath{\alpha}{\text{-Al}}_{2}{\text{O}}_{3})$ exhibit extremely high electrical and mechanical $Q$ factors ($\ensuremath{\approx}{10}^{9}$ at 4 K), which are important characteristics for electromechanical experiments the quantum limit. We report cool down of a bulk sample below superfluid liquid-helium temperature (1.6 K) to as low 25 mK. The electromagnetic properties were characterized microwave frequencies, we observation...