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Identifier 000463258
Title Cavity-enhanced polarimetry techniques for chirality measurements
Alternative Title Τεχνικές πολωσιμετρίας με χρήση οπτικής κοιλότητας για μετρήσεις χειρομορφίας
Author Σαργιάννη, Ζωή Μ.
Thesis advisor Ρακιτζής, Πέτρος
Reviewer Κομίνης, Ιωάννης
Βασιλάκης, Γεώργιος
Abstract In this work we focused on the development of new, continuous-wave (cw) laser, optical-cavity-enhanced techniques for the measurement of the optical activity of chiral substances. All methods are built around a 4-mirror bowtie-shaped optical cavity, supporting two counter-propagating beams, one Clockwise (CW) and one Counter-Clockwise (CCW), for which the chiral effect is of opposite sign. Such cavities have already been employed in pulsed-laser, cavity-enhanced polarimeters, which take advantage of the opposite CW and CCW signals to eliminate common noise and reach polarimetric sensitivities below 10μdeg/√Hz. The desire to achieve even better sensitivities and aim for the measurement of very weak chiral phenom- ena (like the parity-non-conservating optical activity induced by the weak force in certain atomic and molecular transitions) was the incentive to investigate replacing the pulsed with continuous wave lasers in cavity-enhanced polarimenters, and take advantage of their beneficial characteristics: the narrow spectral features and long coherence times, the well-defined intensity profiles and overall higher beam shape qualities, and the increased efficiency in coupling light into and out of the optical cavity, which increases the flux at the detectors of photons which have interacted with the sample; a prerequisite for increased polarimetric sensitivity. We designed and implemented three experimental schemes: a cw-Ring-Down technique, a direct frequency metrology method, and a simple single or dual mod- ulation/demodulation scheme. In this thesis we discuss the implementation details and performance of each method, whether we intend to investigate them further and the steps required for their improvement, and our plans for future work along this path. Currently, the latter method has produced the most promising results, demonstrating sensitivities on the order of 10 − 20μdeg/√Hz, with a clear path for improvement in certain regards, and having the added benefit of being the simplest of all methods experimentally.
Language English
Subject Continuous-wave LASER
LASER συνεχούς φωτός
Optical activity
Optical cavity
Optical rotation
PNC
Οπτική ενεργότητα
Οπτική περιστροφή
Παραβίαση της συμμετρίας της ομοτιμίας
Issue date 2024-03-29
Collection   School/Department--School of Sciences and Engineering--Department of Physics--Post-graduate theses
  Type of Work--Post-graduate theses
Permanent Link https://elocus.lib.uoc.gr//dlib/a/7/e/metadata-dlib-1711023235-110955-14016.tkl Bookmark and Share
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