14,511 research outputs found
Commencement 1943 Address Delivered by Carl R. Woodward: Business Citizenship in the Post-War World
An address before a great gathering in Boston last winter was concluded with the following remarks, Ours is the tragic privilege of living in the greatest military crises since Napoleon...
2D Saturable Absorbers for Fibre Lasers
© 2015.Two-dimensional (2D) nanomaterials are an emergent and promising platform for future photonic and optoelectronic applications. Here, we review recent progress demonstrating the application of 2D nanomaterials as versatile, wideband saturable absorbers for Q-switching and mode-locking fibre lasers. We focus specifically on the family of few-layer transition metal dichalcogenides, including MoS2, MoSe2 and WS2
Recent developments in light alloys
This report is intended to cover the progress that has been made in both the manufacture and utility of light alloys in the United States since the first part of 1919. Duralumin is extensively discussed both as to manufacture and durability
AgNb7O18 : an ergodic relaxor ferroelectric
AgNb7O18 is an ergodic relaxor ferroelectric at room temperature with an incipient transition to the nonergodic state. Electron diffraction confirms a locally polar symmetry, while X-ray diffraction perceives a nonpolar structure. All ions are repelled away from zones where NbO6 octahedra are edge-sharing
Towards 'smart lasers': self-optimisation of an ultrafast pulse source using a genetic algorithm
Short-pulse fibre lasers are a complex dynamical system possessing a broad
space of operating states that can be accessed through control of cavity
parameters. Determination of target regimes is a multi-parameter global
optimisation problem. Here, we report the implementation of a genetic algorithm
to intelligently locate optimum parameters for stable single-pulse mode-locking
in a Figure-8 fibre laser, and fully automate the system turn-on procedure.
Stable ultrashort pulses are repeatably achieved by employing a compound
fitness function that monitors both temporal and spectral output properties of
the laser. Our method of encoding photonics expertise into an algorithm and
applying machine-learning principles paves the way to self-optimising `smart'
optical technologies
Genetic algorithm-based control of birefringent filtering for self-tuning, self-pulsing fiber lasers
Polarization-based filtering in fiber lasers is well-known to enable spectral
tunability and a wide range of dynamical operating states. This effect is
rarely exploited in practical systems, however, because optimization of cavity
parameters is non-trivial and evolves due to environmental sensitivity. Here,
we report a genetic algorithm-based approach, utilizing electronic control of
the cavity transfer function, to autonomously achieve broad wavelength tuning
and the generation of Q-switched pulses with variable repetition rate and
duration. The practicalities and limitations of simultaneous spectral and
temporal self-tuning from a simple fiber laser are discussed, paving the way to
on-demand laser properties through algorithmic control and machine learning
schemes.Comment: Accepted for Optics Letters, 12th June 201
Dark solitons in laser radiation build-up dynamics
We reveal the existence of slowly-decaying dark solitons in the radiation
build-up dynamics of bright pulses in all-normal dispersion mode-locked fiber
lasers, numerically modeled in the framework of a generalized nonlinear
Schr\"odinger equation. The evolution of noise perturbations to
quasi-stationary dark solitons is examined, and the significance of background
shape and soliton-soliton collisions on the eventual soliton decay is
established. We demonstrate the role of a restoring force in extending soliton
interactions in conservative systems to include the effects of dissipation, as
encountered in laser cavities, and generalize our observations to other
nonlinear systems
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PaperChain: A Collaborative Healthcare System Grounded in Field Study Work
In this extended abstract we summarise our recent experiences of designing and deploying PaperChain, a system to support real-time information sharing in healthcare work. A guiding principle has been the development of a deep understanding of the work as the foundation for effective system design. We summarise the field work that motivated the development of PaperChain, some of the key findings and the resulting system. We briefly reflect on the benefits gained from undertaking substantial HCI work in the design of a healthcare system
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