4697482_monash_165902.pdf (10.46 MB)
Engineering spasers: models,designs, and applications
thesis
posted on 2017-02-27, 06:03 authored by Rupasinghe, Chanaka SuranjithThe spaser nanolaser, which is the nanoplasmonic counterpart of the laser, enables the generation and amplification of coherent surface plasmons (SPs) by means
of stimulated emission. Spaser opens up a new era of devices which overcome the
speed barriers of electronics and miniaturizing barriers of optics. This research is mainly focused on engineering spaser devices, particulary the guidelines for design optimization, new designs with improved characteristics, and potential applications.
First, a general quantum mechanical model is developed considering the degeneracy of localized SP modes supported by a resonator. Density matrix analysis of this system helps to derive an expression for SP generation rate and identify the tunable parameters for design optimization. The developed model is then applied to optimize a simple spaser design, in which a metal nanosphere is resonantly coupled to a quantum dot, by altering their material and geometrical parameters.
Next, alternative spaser materials are considered. Although not commonly used in
spaser designs, graphene possesses much better plasmonic properties compared to
gold or silver and carbon nanotubes (CNTs) display excellent photoluminescence
properties. Therefore, a new all-carbon spaser design is proposed where a square
shaped graphene nanoflake (GNF) resonator powered by a CNT gain element offering
the advantages of tunability, robustness, flexibility, and thermal stability.
This design is also analyzed employing the general model to determine the different
material and geometric parameters of GNF and CNT influencing the spaser operation. Based on these results, clear spaser design guidelines such as identifying the crucial tuning parameters, fabricating the resonator, choosing the appropriate
gain medium and pumping mechanism, and relative placement of the components
are also sought. Finally, some new applications of spaser nanolasers are proposed and a spaser powered cancer therapy is discussed in detail. In this setup, a large number of tiny nanolasers penetrate tumors to thermally ablate malignant cancer
cells. Hence, this research as a whole contributes towards engineering the spaser
and catalyzing the process of its practical use and commercialization.
History
Campus location
AustraliaPrincipal supervisor
Malin PremaratneAdditional supervisor 1
Weiren ZhuYear of Award
2015Department, School or Centre
Electrical and Computer Systems EngineeringCourse
Doctor of PhilosophyDegree Type
DOCTORATEFaculty
Faculty of EngineeringUsage metrics
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