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2011 International Quantum Electronics Conference (IQEC) and Conference on Lasers and Electro-Optics (CLEO) Pacific Rim incorporating the Australasian Conference on Optics, Lasers and Spectroscopy and the Australian Conference on Optical Fibre Technology
The electromagnetic enhancement that occurs in surface enhanced Raman scattering (SERS) substrates containing gold nanoparticles (NPs) is believed to arise through the generation of localized surface plasmons. We present results that show no SERS signals are obtained when 25 nm diameter gold NPs layered quartz substrates exposed to 2-aminopyridine are illuminated with plasmon resonant 532 nm radiation,...
Strong longitudinal component of the radially polarized mode of the silicon nano fibers theoretically shows 10 times higher excitation efficiency of the surface plasmon resonance than that of the fundamental mode of the same type fiber at 1.1 μm wavelength.
We demonstrate experimentally the generation and near-field imaging of propagating Airy plasmon beams. These self-accelerating plasmons exhibit self-healing properties and enable novel applications of plasmonics and surface optical tweezers.
We demonstrate a plasmonic analogue of the motion dynamics of quantum particles under a linear restoring force bouncing off a barrier located at the equilibrium pisition (quantum paddle balls). Paddle-ball-type plasmonic potentials are achieved in quadratically modulated metal-dielectric-metal strucutures with transverse metallic walls. We show both analytically and numerically, beam revivals, periodic...
We analyze and optimize double-quantum-dot qubit Hamiltonian parameter estimation algorithms based on the Bayesian updating approach. The theoretical framework for measurement and parameter estimation processes are developed, and we provide numerical simulations showing the algorithms' performance.
Long-range quantum communication and its associated repeater network are a necessity for any future quantum Internet. The performance of such networks is currently limited by the time it takes to establish entangled links between the appropriate parties on the network. Typically this scales as the round trip time for a signal to be transmitted between those parties. We present in this talk the design...
We introduce an efficient self-learning swarm-intelligence algorithm for devising feedback-based quantum metrological procedures to replace what is otherwise an difficult and inefficient problem. Our algorithm can be trained with simulated or real-world trials and accommodates experimental imperfections, losses, and decoherence.
The implementation of quantum memory, i.e. a quantum interface between light and matter, is central to advanced applications of quantum information processing and communication [1]. Notably, quantum memories are key ingredients in quantum repeaters [2], which promise extending quantum communication beyond its current distance limit. After a brief review of the working principle of a quantum repeater...
Reactions that occur near the energetic threshold can be very different to those where energy is in excess. In a series of experiments, we have used a narrow linewidth laser to provide a small organic molecule, acetaldehyde (CH3CHO), with a precise amount of energy, and used laser and imaging based techniques to probe the reaction products. In this paper I shall present three different examples of...
A novel high power, broad bandwidth (450–1750nm) probe laser has been successfully constructed and characterized for transient absorption spectroscopy. Supercontinuum pulses are generated using a nanosecond pulsed Q-switched Nd:YAG laser (1064nm, 7 ns, 20 Hz) in 15m photonic crystal fibers. High spectral quality and stable output power have been reported using this technique. The supercontinuum saturates...
Angular-momentum-dependent isotope shifts in nine high-energy Rydberg levels of xenon have been measured by sub-Doppler two-photon excitation spectroscopy, using narrowband nanosecond pulses of coherent ultraviolet light at 207–209 nm generated by nonlinear-optical conversion processes.
Thermal relaxation of whispering-gallery mode frequencies gives the thermal conductivity of the ambient gas. Measuring this at various pressures allows determination of the accommodation coefficient of the gas on the microresonator's surface coating.
We discuss methods to characterize single nanoparticles simultaneously by polarisability, refractive index and mass using toroidal microresonators. A new technique to determine the refractive index via mode-splitting allows us to size the nanoparticles.
We effectively suppressed a nonresonant background, which is general issue of femtosecond-laser based multiplex CARS spectroscopy, by applying phase sensitive detection for our rapid phase-modulation CARS method [3]. The modulation phase of each spectral measurement can be extracted from an interference intensity between a narrowband probe and a broadband pulse. We demonstrated the method with a sample...
We demonstrate self-trapped laser beams carrying optical vortices in nematic liquid crystals. We experimentally observe astigmatic transformations of vortex beams into spiralling dipole azimuthons accompanied by a nontrivial power-dependent charge-flipping of on-axis phase dislocations.
The self-diffraction effect was used to improve temporal contrast of femtosecond pulse by about four-order of magnitudes. This self-diffraction effect was also used to measure a 55fs pulse based on the self-referenced spectral interferometry method.
Nonlinear refraction of liquids C6H6, C6H5Cl, C6H5Br, and C6H5I was investigated, for the first to our knowledge, using the Z-scan technique with 82 MHz 35 fs laser pulses at 800 nm. For all samples studied a negative lensing effect was observed, opposite to that obtained with 10 Hz 19 picosecond laser pulses. The negative lensing effect was found to increase with the pulse train width and gradually...
Indium oxide (In2O3) films grown on MgO substrates by thermal oxidation were excited by femtosecond laser pulses having photon energy lower than the bandgap. The emission of terahertz (THz) pulse was observed using time domain spectroscopy in the reflection-geometry excitation. Results show that THz generation saturates at an excitation fluence of ∼400 nJ/cm2. Although two-photon absorption has been...
We report on the terahertz (THz) emission from n-GaAs/p-GaSb and /p-InAs/n-GaSb structures using a 1.55 μm femtosecond laser excitation. The effect of the n-GaAs thin film on a p-GaSb substrate is investigated. Significant THz emission from n-GaAs/p-GaSb compared to bare p-GaSb is observed and could be attributed to the built-in field at the interface of the sample. The comparison with a bulk p-InAs...
Antiferromagnetic resonance in orthoferrite NdFeO3 has been investigated using terahertz time-domain spectroscopy. A resonance at 0.5 THz was detected which was assigned to the AF-mode of the antiferromagnetic spin precession.
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