Beam Propagation Modelling of Whispering Gallery Microcavities




Cheraghi Shirazi, Mohammad Amin

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Whispering Gallery Mode (WGM) microcavities have a wide range of applications from fundamental physics researches to engineering applications due to their ultra high quality factor (Q). For example, an ultra-high Q WGM cavity can be used as an bio/nanosensor since a nano particle bound to the surface of the cavity will result in a resonance wavelength shift. In the last decade lots of research have been conducted on this topic, as a result, WGM biosensors are emerging as one of the mainstream senors. This thesis presents an efficient beam propagation method (BPM) simulation tool to study the light propagation behaviour in WGM cavities. Using this tool, the perturbation of the cavity properties caused by a polystyrene nano bead attached to the surface of a WGM silica microcavity is investigated. Furthermore, we numerically verify a three times sensitivity enhancement by fabricating a nanohole at the surface of the WGM cavity sensor. In addition, we study the open cavity structures, cavity-waveguide coupling, huge WGM cavities, and deformed microcavities radiation. Finally, the impact of fabrication inaccuracy on asymmetric WGM cavities is investigated in terms of quality factor degradation.



Micro-optical devices, Detection, WGM, BPM, Resonators