Ringdown spectroscopy (RDS) is an absorption spectroscopic and detection
technique that makes use of an optical cavity to realize a long effective pathlength
through a sample and to render the measurement independent of intensity. These two
features give RDS an advantage over traditional absorption techniques and allows its
application in measuring concentrations of strongly absorbing analytes present in trace
amounts, or in measuring weak absorptions for analytes in higher concentrations. The
resonant optical cavities used here are created from optical fibre. This permits the easy
construction of an inexpensive apparatus for RDS. The performance of various cavity
geometries (linear, circular) in three ranges of the visible and near infrared spectrum (405,
800, and 1550 nm) was examined. Concurrent multiexponential decays arising from core
modes, cladding modes, and amplified spontaneous emission were analyzed in the
framework of an exponential decay model transformed into the frequency domain.
The small mode field diameter of light within a fibre is well suited to probing very
small liquid volumes on the order of pico- or femtolitres. This uniquely positions optical
waveguide-based RDS for application in absorption detection for separation techniques
such as capillary electrophoresis (CE) and high performance liquid chromatography
(HPLC) where high time resolution detection is required across narrow separation
channels. The experimental and theoretical work presented here was preformed with an
eye towards this purpose. / Thesis (Master, Chemistry) -- Queen's University, 2007-07-04 16:23:53.173
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:OKQ.1974/436 |
| Date | 05 July 2007 |
| Creators | Trefiak, Nicholas Ronald |
| Contributors | Queen's University (Kingston, ON.). Theses (Queen's University (Kingston, ON.)) |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
| Type | Thesis |
| Format | 5154273 bytes, application/pdf |
| Rights | This publication is made available by the authority of the copyright owner solely for the purpose of private study and research and may not be copied or reproduced except as permitted by the copyright laws without written authority from the copyright owner. |
| Relation | Canadian Theses |
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