65 research outputs found
One- and two-photon pumped organic semiconductor lasers
No full textThis thesis describes a number of studies on organic semiconductors focused around using them as gain media for lasers. The photophysical properties of organic semiconductors are studied using a wide range of experimental techniques, allowing the evaluation of new materials and novel excitation schemes for use in organic semiconductor lasers.
Polyfluorene is a well-established conjugated polymer laser gain medium and in this thesis its excellent lasing properties are combined with its two photon absorption properties to demonstrate a tunable two-photon pumped solid-state laser based on a commercially available organic semiconductor.
A family of bisfluorene dendrimers was studied using a number of photophysical techniques to evaluate their potential as laser materials. Distributed feedback lasers based on one of the dendrimers are demonstrated with lasing thresholds comparable to polyfluorene. The same materials were found to have enhanced two-photon absorption properties in comparison to polyfluorene, leading to the fabrication of tunable two-photon pumped dendrimer lasers.
A member of a novel family of star-shaped oligofluorene truxenes was evaluated as a laser gain material and the distributed feedback lasers made from them show some of the lowest lasing thresholds reported for organic semiconductors, partly as a consequence of exceptionally low waveguide losses in comparison to other single-material thin films.
Finally, an organic laser dye is blended with a conjugated polymer, where the dye molecules harvest the excitation light of a GaN laser diode and transfer its energy to the polymer molecules. This is the first time such a scheme is used in an organic laser and in combination with a novel surface-emitting distributed Bragg reflector resonator allows the demonstration of a diode-pumped organic laser, a significant step towards simplifying organic lasers
In situ micro- and macro-Raman investigation of the redox couple behavior in DSSCS
No full textAbstract not availableA.G. Kontos, T. Stergiopoulos, G. Tsiminis, Y.S. Raptis, P. Falara
Fabrication of subwavelength surface gratings on exposed-core microstructured optical fibres
No full textWarren-Smith, S.; Tsiminis, G.; Robertson, I.; Turnbull, G.; Samuel, I.; Spooner, N.; Monro, T. M.http://www.aomevents.com/ACMMICON
Measuring nitroaromatic explosives using polymer-coated microstructured optical fibers
No full textOral presentation in Technical Session 3- Chemical and material sensing. Tuesday 10 December 1400–1230Fenghong Chu, Georgios Tsiminis, Catherine E. Lang, Nigel A. Spooner and Tanya M. Monr
A two-photon pumped polyfluorene laser
No full textAbstract not availableGeorgios Tsiminis, Arvydas Ruseckas, Ifor D. W. Samuel, and Graham A. Turnbul
Raman detection of hydrogen peroxide in suspended core optical fibers
No full textPoster presentation Also published as book chapter: OFS2012: 22nd International Conference on Optical Fiber Sensors / Y. Liao, W. Jin, D. D. Sampson, R. Yamauchi, Y. Chung, K. Nakamura, Y. Rao (eds.): 842181The first demonstration of a detection scheme for hydrogen peroxide based on Raman spectroscopy in suspended core optical fibers is presented. This detector combines the advantages of Raman spectroscopy, such as the unique identification of a molecular fingerprint, with a microstructured fiber architecture, which enables low volumes processing and detection. Hydrogen peroxide is chosen as a target molecule since it is a key component in home-made explosives. These results highlight the feasibility of the proposed scheme as a low false-positive detection platform.G. Tsiminis, N. A. Spooner and T. M. Monr
Measurements of vitamin B12 in human blood serum using resonance Raman spectroscopy
No full textVitamin B12 (cobalamin) deficiency has been identified as a potential modifiable risk factor for dementia and Alzheimer’s disease. In this work we present an optical sensor based on resonance Raman spectroscopy for rapid measurements of vitamin B12 in human blood serum with minimum sample preparation.G. Tsiminis, E. P. Schartner, J. L. Brooks, M. R. Hutchinso
Sensing explosives with suspended core fibers: Identification and quantification using Raman spectroscopy
No full textThis works demonstrates the use of suspended core optical fibers as a platform for explosives detection in solution using Raman spectroscopy. This architecture combines small sampling volumes with long light-analyte interaction lengths, resulting in identification of minute quantities of explosives in solutions. In addition, the Raman signature of the solvent is used as an internal calibration standard to allow quantification of the detected molecule. Our results show detection of sub-microgram amounts of hydrogen peroxide (H2O2) in aqueous solution, a molecule difficult to detect as it lacks the nitroaromatic units, characteristic of trinitrotoluene (TNT) based explosives, which are usually targeted by traditional optical methods such as fluorescence. The same platform without any modifications can also be used to identify and quantify comparable amounts of 1,4-dinitrobenzene (DNB), a substitute molecule for TNT. These results highlight the capability of suspended-core fibers as small, cost-efficient and low-volume explosives sensors.Georgios Tsiminis, Fenghong Chu, Nigel A. Spooner and Tanya M. Monr
Extruded single ring hollow core optical fibers for Raman sensing
No full textLink to a related website: https://digital.library.adelaide.edu.au/dspace/bitstream/2440/92476/2/hdl_92476.pdf, Open Access via UnpaywallAbstract not availableG. Tsiminis, K. J. Rowland, H. Ebendorff-Heidepriem, N. A. Spooner and T. M. Monr
Generating and measuring photochemical changes inside the brain using optical fibers: exploring stroke
No full textAbstract not availableGeorgios Tsiminis, Thomas S. Klarić, Erik P. Schartner, Stephen C. Warren-Smith, Martin D. Lewis, Simon A. Koblar, and Tanya M. Monr
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