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Your search keyword '"Dell, A. M."' showing total 47 results
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47 results on '"Dell, A. M."'

44. Recent advances in SWIR MEMS-based tunable Fabry-Pérot microspectrometers

Author

Antoszewski, J., Nguyen, T., Martyniuk, M., Dell, J. M., and Faraone, L.

Abstract

Recent progress in short wavelength infrared MEMS based Fabry-Pérot microspectrometers at The University of Western Australia is presented. The original monolithic approach has been replaced with a hybrid one due to HgCdTe restricting the thermal budget and affecting the quality of structural silicon nitride films. The spectral resolution has been improved by introducing five layer Bragg mirrors and by limiting the electrostatically actuated top mirror bowing and tilting using stress balancing between layers. In effect the FWHM has been reduced to 30nm at ~2.0m in comparison to the ideal theoretical mid-range value of 9nm. Analysis of mirror profiles shows that this difference is a result of remaining mirror imperfections.

Published
2011
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45. Vertical transport in InAs/GaSb type-II strained layer superlattices for infrared focal plane array applications

Author

Umana-Membreno, G. A., Klein, B., Kala, H., Antoszewski, J., Gautam, G., Kutty, M. N., Plis, E., Dell, J. M., Krishna, S., and Faraone, L.

Abstract

In this work, we report on the measurement of vertical transport parameters in p-doped InAs/GaSb type-II superlattices for long-wavelength infrared detectors. Variable magnetic eld geometrical magnetoresistance mea- surements have been employed to extract the vertical transport parameters, since the Hall-eect technique cannot be employed in the vertical transport conguration. The room-temperature magnetoresistance measurements were performed employing a kelvin-mode set up, at electric elds not exceeding 25 V/cm and at magnetic eld intensities up to 12 T. The measured magnetoresistance, shown to exhibit multiple-carrier conduction charac- teristics, were analyzed using a high-resolution mobility spectrum analysis technique. It is shown that, at room temperature, the electrical conductivity of the sample is due to four distinct carriers, associated with the major- ity carrier holes, sidewall inversion layer electrons, and two minority carrier electrons likely associated with two distinct conduction band levels.

Published
2011
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46. On the accuracy of decay constant measurement by swept-cavity heterodyne cavity ringdown spectroscopy

Author

Silva, K. K. M. B. Dilusha, van der Walt, Aislinn, Dell, John M., and Faraone, Lorenzo

Abstract

Cavity ringdown spectroscopy (CRDS) measures the decay time, of a resonant optical cavity containing a measurand, as a function of optical frequency. The measurand is identified and quantified by the cavity decay time, which is modified by the measurand within. As coupling light into a high-finesse optical cavity is difficult, the throughput of the cavity is small. A recent variant, swept-cavity heterodyne CRDS, interferes backward escaping cavity light, with light reflected from the cavity input mirror, providing better signal sensitivity due to the heterodyne advantage. The measured interference signal is demodulated and log-amplified to produce a signal whose slope is representative of the cavity decay time. This paper, for the first time, examines the conditions required for high-fidelity measurements of the cavity decay time using swept-cavity heterodyne CRDS and log-amplification technique. We demonstrate that, due to the very large bandwidth and dynamic range of the log-amplifier, for realistic measurement conditions, the log-amplifier does not impose any significant restrictions on the measurement accuracy. We also demonstrate, however, the measurement accuracy is limited by two factors, the detector bandwidth, and segment of acquired data used to measure the slope.

Published
2011
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