University of Illinois Urbana-Champaign

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

Reboli, Thomas O

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

Description

Title
Quantum beating of rubidium: Interference between atomic coherences and long range atom-atom interactions
Author(s)
Reboli, Thomas O
Issue Date
2024-12-04
Director of Research (if dissertation) or Advisor (if thesis)
Eden, J. Gary
Doctoral Committee Chair(s)
Eden, J. Gary
Committee Member(s)
  • Dragic, Peter
  • Lorenz, Virginia
  • Goldschmidt, Elizabeth
  • Zhao, Yang
Department of Study
Electrical & Computer Eng
Discipline
Electrical & Computer Engr
Degree Granting Institution
University of Illinois at Urbana-Champaign
Degree Name
Ph.D.
Degree Level
Dissertation
Keyword(s)
  • 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
Abstract
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.
Graduation Semester
2024-12
Type of Resource
Thesis
Handle URL
https://hdl.handle.net/2142/127486
Copyright and License Information
Copyright 2024 Thomas Reboli

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