Abstract |
In the present thesis is presented an analysis on the potassium (K+) ion-exchange process in
borosilicate glass, optical fiber whispering gallery mode cavities. The ion-exchange was
achieved using the melt bath technique in a potassium nitrate melt, for typical times of 11, 22
and 44 hours. With the help of a tapered optical fiber coupler, whispering gallery mode spectra
were obtained, while by applying longitudinal strain on the cavity, the relevant mode shifting
effects emerge, as well as the impact of the ion-exchange process on the photoelastic properties
of the glass cavity material. To gain a better insight, energy-dispersive X-ray spectroscopy
revealed the concentrations profiles of the potassium and sodium ions in different depths from
the cavity’s circumference, COMSOL Multiphysics simulations provided a valid digital
representation of the system, and to investigate the effect of non-symmetrical ion-migration and
corresponding refractive index annular changes, ion-exchanged cavities we thermally poled.
Lastly, in order to study the Young’s modulus modifications introduced by the ion-exchange
process, the hardness Knoop was measured using the micro-indentation method on typical BK-7
slabs that had undergone the same treatment.
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