Browsing Administrative Staff Authors by Date of Publication
Now showing items 21-40 of 820
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Hot-exciton relaxation in CdxZn1-xTe/ZnTe multiple quantum wells
(1991)We have observed the creation of hot excitons at high momentum in CdxZn1-xTe multiple quantum wells and subsequent relaxation by LO-phonon emission to give sharp luminescence lines superimposed on a broader background. The ... -
Bistable self-electro-optic operation of strained In0.1Ga0.9As/GaAs asymmetric Fabry Perot modulators
(1991)We report bistable operation of a strained-layer InGaAs/GaAs asymmetric Fabry-Perot optical modulator configured as a self-electro-optic effect device (SEED) operating in reflection mode. Bistable loops are observed from ... -
Room-temperature exciton luminescence in II-VI quantum wells
(1991)We observe free excitons in absorption and emission at room temperature in Cd0,2sZne.7sTe/ ZnTe multiple quantum wells. A large overlap between luminescence and absorption peaks observed at 10 K is maintained up to room ... -
A digital signal processing index of hand tremor
(1992)An index of hand tremor is formulated from the data obtained from the analysis of the cylindrical grip strength. The tremor signal is extracted digitally from the data and the mean square power calculated. The ... -
All-optical clock distribution with synchronous frequency division and multiplication
(1992)A master optical clock from a mode locked laser is distributed to two slave twin section lasers. One slave laser divides the optical modulation frequency by 2, the other slave laser multiplies the frequency by 2. It is ... -
A personal communicator of the vocally handicapped
(IEEE, 1992)An affordable personal communicator which allows full control of the voice has been designed and developed. The aid employs coded digitised speech in an efficient manner, coupled with specif- hardware in an attempt to ... -
All-optical synchronization and frequency division of mode-locked pulses
(1992)We report all-optical synchronization and frequency division of mode-locked input signals, using a selfpulsating laser diode. The performance of mode-locked and sinusoidal input signals are compared. Synchronization ... -
All optical timing extraction with frequency division using a twin section laser diode.
(1993)All-optical timing extraction from a coded line signal with division of the extracted clock frequency is demonstrated using a single twin-section self-pulsating laser diode. Either the bit-rate clock or a submultiple ... -
The influence of the unlocked characteristics of a self-pulsating laser diode on synchronization
(1993)All-optical synchronization and timing extraction based on self-pulsating twin section lasers has been demonstrated. We investigate the variation of the unlocked full-widthat- half-maximum of the fundamental of the RF ... -
Carrier lifetimes in strained InGaAs/(Al)GaAs multiple quantum wells
(1993)The etfect of strain, strain relief, and barrier design on the carrier lifetime in InGaAs/(Al)GaAs multiple-quantum-well samples is investigated. Carriers lifetimes are measured in samples with varying amount of strain, ... -
A fully abstract denotational model for higher-order processes
(IEEE Computer Society Press, 1993)A higher-order process calculus is defined in which one can describe processes which transmit as messages other processes; it may be viewed as a generalization of the lazy ?-calculus. The authors present a denotational ... -
Strain effect on the optical nonlinearity in an InGaAs/GaAs asymmetric Fabry-Perot modulator.
(American Physical Society, 1993)The effect of strain on the optical nonlinearities and operation of an all-optical asymmetric Fabry-Perot italon is investigated. A high reflectivity modulation of 60% is reported with a contrast ratio of 12.2:1 and ... -
Neurofilament expression in human T lymphocytes
(British Society for Immunology, 1993)The expression of intermediate filaments in normal cells is mainly determined by their embryonal developmental origin. Flow cytometry using monoclonal antibody RT97 demonstrated that neurofilament was detectable in the ... -
Electro-optic modulation using asymmetric Fabry-Perot laser diode amplifiers.
(1994)We report the use of laser diode amplifiers, whose facets have unequal mirror reflectivities, as asymmetric Fabry-Perot modulators. Due to the presence of optical gain in these devices we observe modulation of reflected ... -
Gastric T lymphocyte responses to Helicobacter pylori in patients with H pylori colonisation
(BMJ, 1994)Helicobacter pylori has been identified as a dominant factor in the pathogenesis of duodenal ulcer. The aim of this study was to examine peripheral blood and gastric lymphocyte proliferation and cytokine production in ... -
Very low saturation densities in strained InGaAs/AlGaAs multiple quantum wells
(1994)The saturation of excitonic absorption in strained InGaAs/AlGaAs quantum wells is systematically measured as a function of strain. By comparison with an unstrained GaAs/AlGaAs quantum well sample a reduction by a factor ... -
Growth and characterization of an epitaxially grown ZnSSe/MnZnSSe distributed Bragg reflector
(1995)A Bragg reflector consisting of a 25-period MnZnSSe/ZnSSE Bragg stack is reported. The II?VI semiconductor structure was grown by molecular beam epitaxy on a GaAs ~100! epilayer. Structural characterization of the Bragg ...