Quantum beating of rubidium: Interference between atomic coherences and long range atom-atom interactions

Wave packets are established among the 7S_1/2 and 5D_5/2 states of atomic rubidium and are probed via terahertz pump-probe quantum beat spectroscopy. Interferences between the 5D_5/2--5P_3/2 and 5P_3/2--5S_1/2 coherences, occurring at 386.4 and 384.2~THz respectively, are observed at their difference frequency of 2.1~THz. Fano windows are observed in the spectra of this difference frequency, which are controllable by varying the pump-probe crossing angle and background rubidium number density. These tunable spectral features have present likely evidence of control over multiple wave packet decay channels, with the ability to selectively drive and interfere these processes through nonlinear excitation mechanisms. To further explore the possible applications of this unique form of spectroscopy, measurements of quantum beats at 18.225~THz occurring from the 7S_1/2 and 5D_5/2 states of rubidium were taken in the presence of varying pressures of argon, krypton, and xenon. Observed broadening and frequency shifting rates were calculated and treated with a classical impact theory. To our knowledge, this is the first application of this theory to a quantum system in general, and allowed for the investigation of rubidium-rare gas interaction forces at both small and large inter-atomic potentials by monitoring quantum beat spectra.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Electrical & Computer Engr

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2024

Author dc:creator

• Reboli, Thomas O

Contributors dc:contributor

• Eden, J. Gary
• Dragic, Peter
• Lorenz, Virginia
• Goldschmidt, Elizabeth
• Zhao, Yang

• Quantum Beating
• Quantum Beat Spectroscopy
• Terahertz Quantum Beats
• Ultrafast
• Alkali
• Rubidium
• Wave Packet Dynamics
• Four Wave Mixing
• Wave Packet Interference
• Long Range Interactions
• Potential Energy Curves
• Fano Resonances
• Coherence Control

Statement dc:rights

• Copyright 2024 Thomas Reboli

Language dc:language

en, eng

Handle dc:identifier

https://hdl.handle.net/2142/127486

OAI record oai:identifier

https://www.ideals.illinois.edu/oai-pmh?verb=GetRecord&metadataPrefix=etdms&identifier=oai%3Awww.ideals.illinois.edu%3A2142%2F127486