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Title: Electromagnetically induced transparency and dark fluorescence in a cascade three-level diatomic lithium system

Abstract

Following our previous brief report [Phys. Rev. Lett. 88, 173003 (2002)], we report here a detailed study of electromagnetically induced transparency (EIT) and dark fluorescence in a cascade three-level diatomic lithium system using optical-optical double resonance (OODR) spectroscopy for both resonance and off resonance coupling. When a strong coupling laser couples the intermediate state A {sup 1}{sigma}{sub u}{sup +}(v=13,J=14) to the upper state G {sup 1}{pi}{sub g}(v=11,J=14) of {sup 7}Li{sub 2}, the fluorescence from both A {sup 1}{sigma}{sub u}{sup +} and G {sup 1}{pi}{sub g} states was drastically reduced as the weak probe laser was tuned through the resonance transition between the ground state X {sup 1}{sigma}{sub g}{sup +}(v=4,J=15) and the excited state A {sup 1}{sigma}{sub u}{sup +}(v=13,J=14). The strong coupling laser makes an optically thick medium transparent for the probe transition. In addition, the fact that fluorescence from the upper state G {sup 1}{pi}{sub g}(v=11,J=14) was also dark when both lasers were tuned at resonance implies that the molecules were trapped in the ground state. We used density matrix methods to simulate the response of an open molecular three-level system to the action of a strong coupling field and a weak probe field. The analytical solutions were obtained undermore » the steady-state condition. We have incorporated the magnetic sublevel (M) degeneracy of the rotational levels in the line shape analysis and report |M| dependent line shape splitting. Our theoretical calculations are in excellent agreement with the observed fluorescence spectra. We show that the coherence is remarkably preserved even when the coupling field was detuned far from the resonance.« less

Authors:
 [1];  [2]
  1. Department of Physics and Astronomy, Penn State Berks, Tulpehocken Road, P.O. Box 7009, Reading, Pennsylvania 19610 (United States)
  2. Physics Department, Temple University, Philadelphia, Pennsylvania 19112 (United States)
Publication Date:
OSTI Identifier:
20787164
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review. A; Journal Volume: 73; Journal Issue: 4; Other Information: DOI: 10.1103/PhysRevA.73.043810; (c) 2006 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
74 ATOMIC AND MOLECULAR PHYSICS; ANALYTICAL SOLUTION; COUPLING; DENSITY MATRIX; FLUORESCENCE SPECTROSCOPY; GROUND STATES; INTERMEDIATE STATE; LASERS; LITHIUM; MOLECULES; OPACITY; RADIATION PRESSURE; RESONANCE; RESONANCE FLUORESCENCE; ROTATIONAL STATES; STEADY-STATE CONDITIONS; TRAPPING

Citation Formats

Qi Jianbing, and Lyyra, A. Marjatta. Electromagnetically induced transparency and dark fluorescence in a cascade three-level diatomic lithium system. United States: N. p., 2006. Web. doi:10.1103/PHYSREVA.73.0.
Qi Jianbing, & Lyyra, A. Marjatta. Electromagnetically induced transparency and dark fluorescence in a cascade three-level diatomic lithium system. United States. doi:10.1103/PHYSREVA.73.0.
Qi Jianbing, and Lyyra, A. Marjatta. Sat . "Electromagnetically induced transparency and dark fluorescence in a cascade three-level diatomic lithium system". United States. doi:10.1103/PHYSREVA.73.0.
@article{osti_20787164,
title = {Electromagnetically induced transparency and dark fluorescence in a cascade three-level diatomic lithium system},
author = {Qi Jianbing and Lyyra, A. Marjatta},
abstractNote = {Following our previous brief report [Phys. Rev. Lett. 88, 173003 (2002)], we report here a detailed study of electromagnetically induced transparency (EIT) and dark fluorescence in a cascade three-level diatomic lithium system using optical-optical double resonance (OODR) spectroscopy for both resonance and off resonance coupling. When a strong coupling laser couples the intermediate state A {sup 1}{sigma}{sub u}{sup +}(v=13,J=14) to the upper state G {sup 1}{pi}{sub g}(v=11,J=14) of {sup 7}Li{sub 2}, the fluorescence from both A {sup 1}{sigma}{sub u}{sup +} and G {sup 1}{pi}{sub g} states was drastically reduced as the weak probe laser was tuned through the resonance transition between the ground state X {sup 1}{sigma}{sub g}{sup +}(v=4,J=15) and the excited state A {sup 1}{sigma}{sub u}{sup +}(v=13,J=14). The strong coupling laser makes an optically thick medium transparent for the probe transition. In addition, the fact that fluorescence from the upper state G {sup 1}{pi}{sub g}(v=11,J=14) was also dark when both lasers were tuned at resonance implies that the molecules were trapped in the ground state. We used density matrix methods to simulate the response of an open molecular three-level system to the action of a strong coupling field and a weak probe field. The analytical solutions were obtained under the steady-state condition. We have incorporated the magnetic sublevel (M) degeneracy of the rotational levels in the line shape analysis and report |M| dependent line shape splitting. Our theoretical calculations are in excellent agreement with the observed fluorescence spectra. We show that the coherence is remarkably preserved even when the coupling field was detuned far from the resonance.},
doi = {10.1103/PHYSREVA.73.0},
journal = {Physical Review. A},
number = 4,
volume = 73,
place = {United States},
year = {Sat Apr 15 00:00:00 EDT 2006},
month = {Sat Apr 15 00:00:00 EDT 2006}
}
  • Laser cooling is theoretically investigated in a cascade three-level scheme, where the excited state of a laser-driven transition is coupled by a second laser to a top, more stable level, as for alkaline-earth-metal atoms. The second laser action modifies the atomic scattering cross section and produces temperatures lower than those reached by Doppler cooling on the lower transition. When multiphoton processes due to the second laser are relevant, an electromagnetic-induced transparency modifies the absorption of the first laser, and the final temperature is controlled by the second laser parameters. When the intermediate state is only virtually excited, the dynamics ismore » dominated by the two-photon process and the final temperature is determined by the spontaneous decay rate of the top state.« less
  • Electromagnetically induced transparency (EIT) resonance in a {lambda} configuration is obtained when the frequencies of two fields are close to resonance with two of the transitions and their frequency difference matches the frequency of the third transition. In this situation the spectrum of one swept field as a probe gives a simple transparency feature. However, when an additional field drives the third transition the EIT feature associated with the probe is split. This perturbed EIT is illustrated for both single and bichromatic driving fields. In the single-driving-field case a density matrix treatment is shown to be in reasonable agreement withmore » experiment, and in both single and bichromatic cases the structure in the spectrum can be explained using the dressed-state formalism. The dressed states can also be used to account for subharmonic resonances observed in the strong-probe regime.« less
  • We investigate the four-wave mixing (FWM) phenomenon in a three-level bichromatic electromagnetically induced transparency system. Theoretical results predict that the FWM will exhibit a multipeak structure under bichromatic coupling fields. The stronger the coupling fields are, the more FWM the peaks should exhibit. Results of an experiment carried out with cold {sup 87}Rb atoms in a magneto-optical trap agree with the theoretical prediction.
  • We demonstrate laser frequency stabilization to excited state transitions using cascade electromagnetically induced transparency. Using a room temperature Rb vapor cell as a reference, we stabilize a first diode laser to the D{sub 2} transition and a second laser to a transition from the intermediate 5P{sub 3/2} state to a highly excited state with principal quantum number n=19-70. A combined laser linewidth of 280{+-}50 kHz over a 100 {mu}s time period is achieved. This method may be applied generally to any cascade system and allows laser stabilization to an atomic reference in the absence of a direct absorption signal.
  • Electromagnetically induced transparency (EIT) and Autler-Townes (AT) splitting are two phenomena that could be featured in a variety of three-level atomic systems. The considered phenomena, EIT and AT, are similar ''looking'' in the sense that they are both characterized by a reduction in absorption of a weak field in the presence of a stronger field. In this paper, we explicitly set the threshold of separation between EIT and AT splitting in a unified study of four different three-level atomic systems. Two resonances are studied and compared in each case. A comparison of the magnitudes of the resonances reveals two coupling-fieldmore » regimes and two categories of three-level system.« less