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The resonant frequency and
intensity of an optical resonator critically depend on the round-trip
optical path length and loss, and hence refractive indices and
absorption of its constituent materials. In a high-Q optical resonator,
even tiny optical property change can be readily resolved, a unique
capability made possible by the resonantly enhanced photon-matter
interactions. Based on this concept, we have pioneered a novel technique
utilizing optical resonators to probe micro-structural evolution in
glass materials, since structural modifications in these glasses are
often accompanied by a refractive index and/or absorption change.
We have used this
technique to systematically characterized chalcogenide glass thin films
and extracted a wealth of information that is challenging or even
impossible to obtain with traditional metrology tools. For example, in
the As-S glass system, we have measured photo-induced refractive index
change kinetics, two photon absorption (TPA) and thermo-optic
coefficient with unprecedented accuracy [1]. We have also discovered
several interesting new phenomena in this glass material that we will
report shortly. |
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[1]
J. Hu,
N. Carlie, L. Petit, A. Agarwal, K. Richardson, and L. C. Kimerling,
¡°Demonstration of chalcogenide glass racetrack micro-resonators,¡± Opt. Lett.
33, 761-763 (2008); select for the Virtual Journal of Biomedical Optics 3 (5). |
