Cavity-enhanced polarimetry: applications in atomic parity violation and molecular chirality

by Lykourgos Bougas

Institution: University of Crete (UOC); Πανεπιστήμιο Κρήτης
Year: 2014
Keywords: Παραβίαση ομοτιμίας; Πολωσιμετρία; Μοριακή χειρομορφία; Οπτικές κοιλότητες; Atomic parity violation; Polarimetry; Molecular chirality; Optiocal resonators
Record ID: 1153288
Full text PDF: http://hdl.handle.net/10442/hedi/30210


The ability to perform absolute measurements of circular birefringence with high sensitivityis essential to many disciplines of physics, ranging from searches of new physics beyond theStrandard Model, to the detection of chiral molecules in biological samples. In this thesis wedescribe the principles of a novel cavity-enhanced polarimetric technique used for the absolutemeasurement of chirality, by implementing robust background subtraction mechanisms usingtwo novel signal reversals.Atomic Parity Non-Conservation (PNC) experiments are complimentary to high-energy particlephysics experiments and have the potential to detect physics beyond the Standard Model.The Standard Model, and extensions of it, predict a weak parity non-conserving transition amplitudeE1PNC between states of the same parity in atomic systems. Measurement of the E1PNCtransition amplitude is possible through the interference between a dominant parity-allowedtransition. In the vicinity of a parity-allowed magnetic-dipole M1 transition, the interferenceM1-E1PNC leads to natural optical activity. This dissertation explores the possibility of performingPNC optical rotation studies in three new atomic systems, namely xenon (Xe), mercury(Hg) and iodine (I). The feasibility of obtaining observable signals in various transitions of theproposed atomic systems is discussed in detail, and theoretical simulations are presented, suggestingthat PNC measurements with high sensitivity are possible. Furthermore, the abilityof performing PNC measurements along a chain of isotopes in all three systems, and measurementsof nuclear spin-dependent PNC eects for both odd-neutron and odd-proton nuclei isdiscussed. The goal of these pursuits is to provide ratios of the observables along the chain ofisotopes, from which the details of atomic structure should cancel, and to add measurements ofthe anapole moments for these three new nuclei, in addition to the only existing measurementsin Cs and Tl.Towards the construction of a PNC optical rotation experiment, various proof-of-principleexperiments using pulsed laser sources were performed. In these proof-of-principle experiments,the absolute measurement of natural optical activity in the gas phase is proved to be possible,using the two novel signal reversals. In particular, measurements of natural optical activityfrom various chiral molecules in an evacuated and a non-evacuated achiral environment arepresented. The open-air gas-phase measurements are realized for the rst time. We continueby demonstrating the ability of measuring molecular chirality in the liquid phase using smallvolume samples, an application of biological interest.Finally, preliminary studies of a pair of near-degenerate opposite-parity states in atomicXenon are presented. We examine the possibility of performing experiments in search of parity(P) and time-reversal invariance (T) violating phenomena, and we present Stark-shift measurementsof one of the states of interest. Η ικανότητα να πραγματοποιούμε μετρήσεις κυκλικής διπλοθλαστικότητας με μεγάλη…