Phase control of probe response in a Doppler-broadened N-type four-level system

Journal Article · Fri Apr 15 04:00:00 EDT 2011 · Physical Review. A

DOI:https://doi.org/10.1103/PHYSREVA.83.043805· OSTI ID:21544692

Xijun, Fan; Zhongbo, Liu; Ying, Liang; Kening, Jia ^[1]; Dianmin, Tong ^[2]

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1. College of Physics and Electronics, Shandong Normal University, Jinan 250014 (China)
2. School of Physics, Shandong University, Jinan 250100 (China)

In this paper, we investigate theoretically the effect of the relative phase ({phi}) between the probe and driving fields on gain (absorption) and dispersion of the probe field in a Doppler-broadened N-type four-level system with spontaneously generated coherence from different respects. It is shown that gain (absorption) and dispersion are very sensitive to variations in the relative phase, and changing the Doppler width also has an obvious effect on the phase-dependent gain (absorption) and dispersion. When the probe and driving fields have the same propagation directions (copropagating), for the same Doppler width, the dispersion curve with {phi}={alpha} is the same as the gain (absorption) curve with {phi}={alpha}+{pi}/2; however, when the probe and driving fields have opposite propagation directions (counterpropagating), the dispersion curve and gain (absorption) curve are different and the difference becomes more considerable with an increase in Doppler width. In the co- and counterpropagating cases, gain (absorption) and dispersion always vary periodically with varying {phi}, and the period is 2{pi}. By adjusting the value of {phi}, the largest gain (absorption) and dispersion can be obtained, and a large index of refraction without absorption can be realized. Generally speaking, gain decreases with an increase in Doppler width, but by adjusting value of {phi}, at some special values of Doppler width, a larger gain than that without Doppler broadening can be obtained. Our study also shows that gain in the copropagating case is much larger than that in the counterpropagating case.

• OSTI ID: 21544692
• Journal Information: Physical Review. A, Journal Name: Physical Review. A Journal Issue: 4 Vol. 83; ISSN 1050-2947; ISSN PLRAAN
• Country of Publication: United States
• Language: English

Related Subjects

74 ATOMIC AND MOLECULAR PHYSICS
ABSORPTION
CONTROL
DIMENSIONS
DISPERSIONS
DOPPLER BROADENING
LINE BROADENING
OPTICAL PROPERTIES
PERIODICITY
PHYSICAL PROPERTIES
PROBES
REFRACTIVE INDEX
SORPTION
VARIATIONS
WIDTH