Detection systems and algorithms for multiplexed quantum dots

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dc.contributor.advisorPotter, Michael E.
dc.contributor.advisorMessier, Geoffrey G.
dc.contributor.authorGoss, Kelly Christine
dc.date.accessioned2017-12-18T22:31:48Z
dc.date.available2017-12-18T22:31:48Z
dc.date.issued2012
dc.descriptionBibliography: p. 106-110en
dc.description.abstractQuantum Dots (QDs) are semiconductor nanocrystals that absorb light and re-emit at a wavelength dependent on its size and shape. A group of quantum dots can be designed to have a unique spectral emission by varying the size of the quantum dots (wavelength) and number of quantum dots (optical power) [l]. This technology is refered to as Multiplexed Quantum Dots (MxQD) and when it was first proposed, MxQD tags were created with 6 optical power levels and one QD colour or 3 QD colours and 2 optical power levels. It was hypothesized that a realistic limit to the number of tags would be a system of 6 optical power levels and 6 QD colours resulting in 46655 unique tags. In recent work, the fabrication and detection of 9 unique tags [2] was demonstrated which is still far from the predicted capability of the technology. The limitations affecting the large number of unique tags are both the fabrication methods and the data detection algorithms used to read the spectral emissions. This thesis makes contributions toward improving the data detection algorithms for MxQD tags. To accomplish this, a communications system model is developed that includes the inteference between QD colours, Inter-Symbol Interference (ISI), and additive noise. The model is developed for the two optical detectors, namely a Charge-Coupled Device (CCD) spectrometer and photodiode detectors. The model also includes an analytical expression for the Signal-to-Noise Ratio (S R) of the detectors. For the CCD spectrometer, this model is verified with an experimental prototype. With the models in place, communications systems tools are applied that overĀ­come both ISI and noise. This is an improvement over previous work in the field that only considered algorithms to overcome the ISI or noise separately. Specifically, this thesis outlines the proposal of a matched filter to improve SNR, a Minimum Mean Square Error (MMSE) equalizer that mitigates ISI in the presence of noise and a Maximum Likelihood Sequence (MLS) detection algorithm to provide the best detection performance at the cost of higher computational complexity. Simulations demonstrate that the improved data detection algorithms could read 46,655 MxQD tags with over 97% accuracy compared to 11 % or 60% with traditional data detection algorithms for the CCD spectrometer and photo diode detector respectively
dc.format.extentxvii, 112 leaves : ill. ; 30 cm.en
dc.identifier.citationGoss, K. C. (2012). Detection systems and algorithms for multiplexed quantum dots (Doctoral thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca. doi:10.11575/PRISM/4774en_US
dc.identifier.doihttp://dx.doi.org/10.11575/PRISM/4774
dc.identifier.urihttp://hdl.handle.net/1880/105775
dc.language.isoeng
dc.publisher.institutionUniversity of Calgaryen
dc.publisher.placeCalgaryen
dc.rightsUniversity of Calgary graduate students retain copyright ownership and moral rights for their thesis. You may use this material in any way that is permitted by the Copyright Act or through licensing that has been assigned to the document. For uses that are not allowable under copyright legislation or licensing, you are required to seek permission.
dc.titleDetection systems and algorithms for multiplexed quantum dots
dc.typedoctoral thesis
thesis.degree.disciplineElectrical and Computer Engineering
thesis.degree.grantorUniversity of Calgary
thesis.degree.nameDoctor of Philosophy (PhD)
ucalgary.item.requestcopytrue
ucalgary.thesis.accessionTheses Collection 58.002:Box 2086 627942958
ucalgary.thesis.notesUARCen
ucalgary.thesis.uarcreleaseyen
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