Competition between collective and stimulated effects in 130Te2 superfluorescence

Meziane, J.; Oullemine, S.; Amezian, K.; Boursey, E.

doi:10.1016/s0009-2614(02)01279-4

Cited by 7 publications

(3 citation statements)

References 20 publications

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“…In addition, other broadening effects, such as Doppler broadening, are further dephasing mechanisms that can destroy cooperative behavior if their time-scales (importantly the so-called Doppler dephasing time, i.e., the reciprocal of the Doppler width) are smaller than T R and τ D (Meziane et al 2002;Bonifacio & Lugiato 1975). In a thermally relaxed gas, thermal motions are probably the most important dephasing effects and result in line broadenings that correspond to very short dephasing time-scales (e.g., T therm ∼ 10 −3 sec at T = 100 K).…”

Section: Non-ideal Case -Dephasing Effectsmentioning

confidence: 99%

DICKE’S SUPERRADIANCE IN ASTROPHYSICS. I. THE 21 cm LINE

Rajabi

Houde

2016

ApJ

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We have applied the concept of superradiance introduced by Dicke in 1954 to astrophysics by extending the corresponding analysis to the magnetic dipole interaction characterizing the atomic hydrogen 21 cm line. Although it is unlikely that superradiance could take place in thermally relaxed regions and that the lack of observational evidence of masers for this transition reduces the probability of detecting superradiance, in situations where the conditions necessary for superradiance are met (i.e., close atomic spacing, high velocity coherence, population inversion, and long dephasing time-scales compared to those related to coherent behavior), our results suggest that relatively low levels of population inversion over short astronomical length-scales (e.g., as compared to those required for maser amplification) can lead to the cooperative behavior required for superradiance in the ISM. Given the results of our analysis, we expect the observational properties of 21-cm superradiance to be characterized by the emission of high intensity, spatially compact, burst-like features potentially taking place over short periods ranging from minutes to days.

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Section: Non-ideal Case -Dephasing Effectsmentioning

confidence: 99%

DICKE’S SUPERRADIANCE IN ASTROPHYSICS. I. THE 21 cm LINE

Rajabi

Houde

2016

ApJ

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“…27. There is continued interest in studying SF for improving theoretical understanding, 28 for detecting species concentrations, 29,30 for determining molecular level structure, 31 and in the context of generating new nonlinear effects. 32 The scaling laws for SF can be quantified in terms of the propagation time E for light through the medium and the dipole coupling time R given by R =1/N⌫.…”

Section: B Superfluorescence Scaling Lawsmentioning

confidence: 99%

Collision-induced superfluorescence

2005

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We have studied superfluorescence (SF) in Ca vapor evolving on the 3d4s 3 D J-4s4p 3 P J−1 transitions at 1.9 m by exciting the 4s 21 S 0-4s4p 1 P 1 with a pulsed dye laser. SF is generated following population transfer by spinchanging collisions with an inert gas Ar from the 4s4p 1 P 1 and 3d4s 1 D 2 levels. We show for the first time to our knowledge that the time delay for SF evolution follows the 1 / ͱ N dependence expected for the case of uniform excitation of the vapor column by collisional transfer. Here, N is the number of participating atoms that was measured directly from the photon yield. The measured photon yield for the signal as a function of Ar pressure was found to be consistent with rate equations that simulate the buildup of populations in the 3 D J levels based on known collisional rates. This suggests that collisional rates can be directly inferred on the basis of SF photon yields and the atomic level populations. The pulse shapes for SF show temporal oscillations that depend on two distinct factors. The first is the presence of a number of independently evolving regions in the gain medium, and the second is the presence of spatial modes. Temporal ringing is a well-known effect related to the exchange of energy between the atoms and the radiation field during pulse propagation. However, the temporal ringing observed in this experiment is far more pronounced than in previous SF experiments due to a particular choice of evolution parameters. This should make it feasible to compare our results with detailed numerical simulations that have been carried out previously.

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“…[17][18][19] Therefore, this type of superfluorescence has a potential use as a new high-gain mirrorless laser activity containing other optical media. [20][21][22][23] To date, vibronic structures with zero-phonon lines [9][10][11][12] have been investigated for the emission spectra of chalcogen molecular ions, but vibronic structures in their excitation 11,[24][25][26] and absorption 27) spectra have not been investigated so intensively. In the present paper, we investigate systematically both the excitation and emission spectra of O 2 À molecular ions in potassium halide crystals such as KI, KBr and KCl.…”

Section: Introductionmentioning

confidence: 99%

Vibronic Structures in Excitation and Emission Spectra Characteristics of O₂ ^- Molecular Ions in KI, KBr and KCl Crystals

Sarjono

Baba

Nishidate

et al. 2004

Jpn. J. Appl. Phys.

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The excitation and emission spectra of O 2 À molecular ions in KI, KBr and KCl crystals have systematically been investigated at 8.7 K. The present results for the emission spectra with zero-phonon lines were in good agreement with previous results. From the temperature dependence of their emissions, we found that the luminescence intensities of O 2 À ions still appear at room temperature (RT) and are much stronger than those of other chalcogen molecular ions particularly in a KCl crystal. On the other hand, we found vibronic structures on the low-energy sides of the excitation spectra of KI and KBr:O 2 À crystals, showing several peaks with nearly equidistant spacings. The anharmonic vibrational energies of O 2 À molecular ions in the excited state were obtained from these energy differences, depending on their lattice constants. Using spectroscopic constants calculated from the experimental data, we could construct a configurational-coordinate diagram for an O 2 À center in a KI:O 2 À crystal.

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Competition between collective and stimulated effects in 130Te2 superfluorescence

Cited by 7 publications

References 20 publications

DICKE’S SUPERRADIANCE IN ASTROPHYSICS. I. THE 21 cm LINE

DICKE’S SUPERRADIANCE IN ASTROPHYSICS. I. THE 21 cm LINE

Collision-induced superfluorescence

Vibronic Structures in Excitation and Emission Spectra Characteristics of O₂ ^- Molecular Ions in KI, KBr and KCl Crystals

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Competition between collective and stimulated effects in 130Te2 superfluorescence

Cited by 7 publications

References 20 publications

DICKE’S SUPERRADIANCE IN ASTROPHYSICS. I. THE 21 cm LINE

DICKE’S SUPERRADIANCE IN ASTROPHYSICS. I. THE 21 cm LINE

Collision-induced superfluorescence

Vibronic Structures in Excitation and Emission Spectra Characteristics of O2 - Molecular Ions in KI, KBr and KCl Crystals

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Vibronic Structures in Excitation and Emission Spectra Characteristics of O₂ ^- Molecular Ions in KI, KBr and KCl Crystals