A5085870222- Terahertz technology and applications
- Gyrotron and Vacuum Electronics Research
- Particle Accelerators and Free-Electron Lasers
- Semiconductor Quantum Structures and Devices
- Chalcogenide Semiconductor Thin Films
- Particle accelerators and beam dynamics
- Photonic and Optical Devices
- Spectroscopy and Laser Applications
- Laser Design and Applications
- Laser-Matter Interactions and Applications
- Solid-state spectroscopy and crystallography
- Integrated Circuits and Semiconductor Failure Analysis
- Ion-surface interactions and analysis
- Particle Detector Development and Performance
- Laser-induced spectroscopy and plasma
- Holomorphic and Operator Theory
- Semiconductor materials and devices
- Mathematical Analysis and Transform Methods
- Silicon and Solar Cell Technologies
- Advanced Harmonic Analysis Research
- Plasma Diagnostics and Applications
- Superconducting Materials and Applications
- Magnetism in coordination complexes
- Superconducting and THz Device Technology
- Analytic and geometric function theory
Science and Technology Facilities Council
2017-2023
Cockcroft Institute
2016-2023
Sci-Tech Daresbury
2016-2023
University of Virginia
2021
Daresbury Laboratory
2015-2020
Technology Centre Prague
2020
Walsh University
2020
University of Oxford
1969-2018
Lancaster University
2014
University of St Andrews
2006-2013
Infrared transmission and reflectivity measurements from 1 to 25 \ensuremath{\mu} (microns) have been made on several samples of green alpha (hexagonal) SiC. The residual ray bands observed for the ordinary extraordinary rays. resonance frequencies are 2.380\ifmmode\times\else\texttimes\fi{}${10}^{13}$ ${\mathrm{sec}}^{\ensuremath{-}1}$ (12.60 \ensuremath{\mu}) 2.356\ifmmode\times\else\texttimes\fi{}${10}^{13}$ (12.73 \ensuremath{\mu}), respectively. From high-frequency dielectric constant...
We report a THz radiation source based on the technique of non-collinear phasematched parametric generation. The source, which is compact and operable at room temperature, generates nanosecond pulses peak power energy greater than 1W 5 nJ respectively. continuously tunable over range 1.2-3.05 narrow spectral bandwidth (<100 GHz). use intersecting pump wave cavities results in threshold pulse energies below 1 mJ (from Nd:YAG laser excited 20 W, 500 microsec by quasi-CW diode-laser) close to...
We report a technique for line-narrowing terahertz radiation produced through parametric generation. By incorporating an etalon within the idler-wave cavity of oscillator, is generated with linewidth 1GHz (freerunning 50–100GHz) and center frequency continuously tunable over band &gt;50GHz, settable anywhere coarse tuning range device (1–3THz). When implemented intracavity geometry, pulses duration ∼10ns energy ∼30nJ are at repetition rates up to 400Hz (implying mean powers &gt;10μW...
The low-$T$ conductivity of lightly doped, compensated, crystalline $n$-type GaAs epilayers is described by $\ensuremath{\sigma}={\ensuremath{\sigma}}_{0}\mathrm{exp}[\ensuremath{-}{(\frac{{T}_{0}}{T})}^{s}]+{\ensuremath{\sigma}}_{c}\mathrm{exp}[\frac{\ensuremath{-}({E}_{c}\ensuremath{-}{E}_{F})}{{k}_{B}T}]$. $s$ found to vary from 0.2 0.27, implying that the Coulomb gap in density impurity states plays at best a minor role hopping ($T>1$ K) for...
The sub-luminal phase velocity of electromagnetic waves in free space is generally unobtainable, being closely linked to forbidden faster than light group velocities. requirement effective phase-velocity laser-driven particle acceleration schemes imposes a fundamental limit on the total achievable free-space, and necessitates use dielectric structures waveguides for extending field-particle interaction. Here we demonstrate new travelling-source propagation approach overcoming limits....
The compact linear accelerator for research and applications (CLARA) is an ultrabright electron beam test facility being developed at STFC Daresbury Laboratory. ultimate aim of CLARA to advanced free laser (FEL) schemes that can later be implemented on existing future short-wavelength FELs. In addition, a unique provide high-quality novel concepts ideas in wide range disciplines function as technology demonstrator United Kingdom x-ray FEL facility. built three phases; the first phase, or...
We report a terahertz (THz) source continuously tunable over ~20 GHz with linewidth <100 MHz (close to the transform limit of 1-10 ns pulses) and settable anywhere in range 1-3 THz. The consists an injection-seeded intracavity THz optical parametric oscillator, which exhibits benefits lower threshold enhanced efficiency power similar extracavity device. Linewidth control was achieved <1 mW seed laser pulse energies >5 nJ observed up 68% downconversion pump wave. Spectroscopy 1.4969 carbon...
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSynthesis and antiallergy activity of 4-(diarylhydroxymethyl)-1-[3-(aryloxy)propyl)piperidines structurally related compoundsDavid A. Walsh, Stephen K. Franzyshen, John M. YanniCite this: J. Med. Chem. 1989, 32, 1, 105–118Publication Date (Print):January 1989Publication History Published online1 May 2002Published inissue 1 January 1989https://pubs.acs.org/doi/10.1021/jm00121a022https://doi.org/10.1021/jm00121a022research-articleACS...
We report the use of quasi-phase-matching techniques based on periodically-poled MgO:LiNbO(3) for generation nanosecond duration pulses terahertz radiation in intracavity optical parametric oscillators. Multiple idler-waves are generated with temporal studies indicating that initiating process is expected down-conversion, but followed by cascaded difference frequency generation. A number grating geometries have been explored, revealing presence dual solutions general case. Choice parameters...
A transient eddy current package is being extended to model rotating systems. By allowing the system rotate, induced currents must be modelled. The developed uses "lock-step" approach rotation. As rotation progresses voltages in coil windings change, and depending on driving circuit configuration, source will alter. Coupling an external determine therefore necessary. extensions are discussed, order compute voltages, couple power model. mechanism whereby coupling achieved also discussed.
Blue–violet electroluminescence has been observed in forward-biased zinc-oxide diodes of the metal–insulator–semiconductor variety. The power efficiency was about 0.005% at 300 K. emission spectra can be correlated with those obtained from cathodoluminescence measurements.
ABSTRACT Harmonic power from a 10 cm wavelength glow discharge in neon has been detected down to 8 mm (18th harmonic). The fundamental is fed the waveguide coaxial line terminated by tube. A second smaller coupled extract, harmonic power. With careful matching at each wavelength, tho conversion loss appears fall off only 3-4 du per after an initial drop of 35 da third (lowest measured). typical (12th harmonic) 63 dB, e.g. 20 kw input, m\v output. In general output increases with input until...
Ion implantation of P, V, N, O, Ar and Ne into n-type Li-doped ZnO has been investigated with energy up to 300 keV at dose levels 1012-1016 cm−2. Measurements sheet conductivity Hall mobility as a function anneal temperature have given evidence layers after P V implantation, conductivities 105 times higher than unimplanted Ar-implanted material. It also found that an isochronal sequence, terminated by 1 h, 450 °C vacuum then water quench, is sufficient remove most the electrical effects...
The time-resolved detection of ultrashort pulsed THz-band electric field temporal profiles without an laser probe is demonstrated. A non-linear interaction between a narrow-bandwidth optical and the THz pulse transposes spectral intensity phase information to region, thereby generating whose envelope replicates profile real field. This characterised via autocorrelation based FROG (frequency resolved gating) measurement, hence revealing profile. combination narrow-bandwidth, long duration,...