30,222 research outputs found
Deploying quantum light sources on nanosatellites II: lessons and perspectives on CubeSat spacecraft
To enable space-based quantum key distribution proposals the Centre for
Quantum Technologies is developing a source of entangled photons ruggedized to
survive deployment in space and greatly miniaturised so that it conforms to the
strict form factor and power requirements of a 1U CubeSat. The Small Photon
Entangling Quantum System is an integrated instrument where the pump, photon
pair source and detectors are combined within a single optical tray and
electronics package that is no larger than 10 cm x 10 cm x 3 cm. This footprint
enables the instrument to be placed onboard nanosatellites or the CubeLab
structure aboard the International Space Station. We will discuss the
challenges and future prospects of CubeSat-based missions.Comment: Submitted to SPIE Quantum Information Science and Technology. Paper
number 9648-4
Orbital Angular Momentum Waves: Generation, Detection and Emerging Applications
Orbital angular momentum (OAM) has aroused a widespread interest in many
fields, especially in telecommunications due to its potential for unleashing
new capacity in the severely congested spectrum of commercial communication
systems. Beams carrying OAM have a helical phase front and a field strength
with a singularity along the axial center, which can be used for information
transmission, imaging and particle manipulation. The number of orthogonal OAM
modes in a single beam is theoretically infinite and each mode is an element of
a complete orthogonal basis that can be employed for multiplexing different
signals, thus greatly improving the spectrum efficiency. In this paper, we
comprehensively summarize and compare the methods for generation and detection
of optical OAM, radio OAM and acoustic OAM. Then, we represent the applications
and technical challenges of OAM in communications, including free-space optical
communications, optical fiber communications, radio communications and acoustic
communications. To complete our survey, we also discuss the state of art of
particle manipulation and target imaging with OAM beams
Roadmap on structured light
Structured light refers to the generation and application of custom light fields. As the tools and technology to create and detect structured light have evolved, steadily the applications have begun to emerge. This roadmap touches on the key fields within structured light from the perspective of experts in those areas, providing insight into the current state and the challenges their respective fields face. Collectively the roadmap outlines the venerable nature of structured light research and the exciting prospects for the future that are yet to be realized.Peer ReviewedPostprint (published version
Optical Phonon Limited High Field Transport in Layered Materials
An optical phonon limited velocity model has been employed to investigate
high-field transport in a selection of layered 2D materials for both, low-power
logic switches with scaled supply voltages, and high-power, high-frequency
transistors. Drain currents, effective electron velocities and intrinsic
cut-off frequencies as a function of carrier density have been predicted thus
providing a benchmark for the optical phonon limited high-field performance
limits of these materials. The optical phonon limited carrier velocities of a
selection of transition metal dichalcogenides and black phosphorus are found to
be modest as compared to their n-channel silicon counterparts, questioning the
utility of these devices in the source-injection dominated regime. h-BN, at the
other end of the spectrum, is shown to be a very promising material for
high-frequency high-power devices, subject to experimental realization of high
carrier densities, primarily due to its large optical phonon energy.
Experimentally extracted saturation velocities from few-layer MoS2 devices show
reasonable qualitative and quantitative agreement with predicted values.
Temperature dependence of measured vsat is discussed and found to fit a
velocity saturation model with a single material dependent fit parameter.Comment: 8 pages, 6 figure
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