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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
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Σαργιάννη, Ζωή Μ.
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Thesis advisor
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Ρακιτζής, Πέτρος
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Reviewer
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Κομίνης, Ιωάννης
Βασιλάκης, Γεώργιος
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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.
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Language |
English |
Subject |
Continuous-wave LASER |
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LASER συνεχούς φωτός |
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Optical activity |
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Optical cavity |
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Optical rotation |
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PNC |
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Οπτική ενεργότητα |
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Οπτική περιστροφή |
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Παραβίαση της συμμετρίας της ομοτιμίας |
Issue date |
2024-03-29 |
Collection
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School/Department--School of Sciences and Engineering--Department of Physics--Post-graduate theses
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Type of Work--Post-graduate theses
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Permanent Link |
https://elocus.lib.uoc.gr//dlib/a/7/e/metadata-dlib-1711023235-110955-14016.tkl
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Views |
134 |
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