Low-frequency stimulated emission and induced absorption in a three-level atom

1995 ◽  
Vol 99 (1) ◽  
pp. 429-434
Author(s):  
Constantine Mavroyannis
Keyword(s):  
Low Frequency ◽  
Stimulated Emission ◽  
Induced Absorption ◽  
Level Atom

Induced absorption and stimulated emission in a driven two-level atom

1992 ◽  
Vol 70 (6) ◽  
pp. 427-431 ◽  
Author(s):  
Constantine Mavroyannis
Keyword(s):  
Excited State ◽  
Ground State ◽  
Laser Field ◽  
Low Frequency ◽  
Ultrashort Pulses ◽  
Stimulated Emission ◽  
Spectral Lines ◽  
Laser Photon ◽  
Induced Absorption ◽  
Level Atom

We have considered the induced processes that occur in a driven two-level atom, where a laser photon is absorbed and emitted by the ground and by the excited states of the atom, respectively. In the low-intensity limit of the laser field, the induced spectra arising when a laser photon is absorbed by the ground state of the atom consist of two peaks describing induced-absorption and stimulated-emission processes, respectively, where the former prevails over the latter. Asymmetry of the spectral lines occurs at off-resonance and its extent depends on the detuning of the laser field. The physical, process where a laser photon is emitted by the excited state is the reverse of that arising from the absorption of a laser photon by the ground state of the atom. The former differs from the latter in that the emission of a laser photon by the excited state occurs in the low-frequency regime and that the stimulated-emission process prevails over that of the induced absorption. In this case, amplification of ultrashort pulses is likely to occur without the need of population inversion between the optical transitions. The computed spectra are graphically presented and discussed.

Low-frequency stimulated emission and induced absorption in a three-level atom

1995 ◽  
Vol 99 (3) ◽  
pp. 429-434 ◽  
Author(s):  
Constantine Mavroyannis
Keyword(s):  
Low Frequency ◽  
Stimulated Emission ◽  
Induced Absorption ◽  
Level Atom

Laser threshold of viscous active media in the presence of induced absorption at stimulated emission wavelength

1976 ◽  
Vol 6 (11) ◽  
pp. 1272-1275 ◽  
Author(s):  
G A Abakumov ◽  
L T Makarova ◽  
A P Simonov
Keyword(s):  
Stimulated Emission ◽  
Emission Wavelength ◽  
Induced Absorption ◽  
Laser Threshold ◽  
Active Media

Interference effects in the resonance fluorescence of a three-level atom at high proton densities

1980 ◽  
Vol 58 (7) ◽  
pp. 957-963 ◽  
Author(s):  
Constantine Mavroyannis
Keyword(s):  
Excitation Spectrum ◽  
Beat Frequency ◽  
Low Frequency ◽  
Delta Function ◽  
Resonance Fluorescence ◽  
Interference Effects ◽  
Lorentzian Line ◽  
Level Atom ◽  
Upper Level ◽  
The Stability

A theory on interference effects at high photon densities has been developed for two types of a single three-level atom for which transitions occur: (i) from two different upper levels to a common lower one and (ii) from a common upper level to two different lower levels. The excitation spectrum for the interference effects for the two types of atoms results from the symmetric and antisymmetric interference between the two electronic transitions of the system, respectively. The spectral function for the symmetric modes consists of three Lorentzian lines peaked at the frequencies ω = Δ and ω = Δ ± Ω and having spectral widths of the order of γ0 and 3γ0/4, respectively, where Δ is the beat frequency, Ω is the Rabi frequency, and γ0/2 is equal to the natural linewidth for a photon spontaneously emitted from an isolated atom. The antisy mmetric spectrum consists of the peak of ω = Δ, which has a delta-function distribution indicating the stability of the mode in question, and two Lorentzian lines peaked at ω = Δ ± Ω with radiative widths of the order of γ0/2. The excitation spectrum of each type of atom contains also a Lorentzian line describing the very low frequency mode of the system, respectively.

Collision–induced absorption in gaseous methane at low temperatures

1986 ◽  
Vol 64 (7) ◽  
pp. 763-767 ◽  
Author(s):  
I. R. Dagg ◽  
A. Anderson ◽  
S. Yan ◽  
W. Smith ◽  
C. G. Joslin ◽  
...  
Keyword(s):  
Experimental Data ◽  
Low Temperatures ◽  
Low Frequency ◽  
Frequency Region ◽  
Experimental Results ◽  
Published Data ◽  
Frequency Range ◽  
Simple Method ◽  
Induced Absorption ◽  
Good Agreement

A recently developed theory for collision-induced absorption in methane is compared with experimental results over a wider spectral range and at lower temperatures than previously reported. The present experimental results covering the frequency range below 400 cm−1 exhibit good agreement with other recently published data. The theory shows excellent agreement with experiment in the low-frequency region below approximately 200 cm−1 but underestimates the experimental data somewhat at higher frequencies. Possible theoretical reasons for this discrepancy are given. The theory represents a simple method of obtaining a good estimate of the collision-induced absorption spectra of methane in this frequency region and for extrapolating to lower temperatures for which experimentation is not feasible. In addition, the moments α1 and γ1are compared with earlier determinations and indicate good agreement with the previously obtained values for the octupole and hexadecapole moments of methane.

Stimulated emission in a four-level atom

1993 ◽  
Vol 5 (6) ◽  
pp. 317-326 ◽  
Author(s):  
C Mavroyannis
Keyword(s):  
Stimulated Emission ◽  
Level Atom

Transfer-of-coherence-enhanced stimulated emission and electromagnetically induced absorption in Zeeman split F_g-->F_e=F_g−1 atomic transitions

2007 ◽  
Vol 32 (16) ◽  
pp. 2318 ◽  
Author(s):  
R. Meshulam ◽  
T. Zigdon ◽  
A. D. Wilson-Gordon ◽  
H. Friedmann
Keyword(s):  
Stimulated Emission ◽  
Induced Absorption ◽  
Atomic Transitions ◽  
Electromagnetically Induced Absorption

Submillimetric and millimetric collision-induced absorption spectra in compressed gaseous nitrogen using very low-frequency optical source

1991 ◽  
Vol 69 (10) ◽  
pp. 1264-1272 ◽  
Author(s):  
R. Occelli ◽  
H. Chaaban ◽  
J. M. Moynault ◽  
R. Coulon ◽  
A. Balsamo
Keyword(s):  
Nonlinear Crystal ◽  
Relaxation Times ◽  
Low Frequency ◽  
Theoretical Models ◽  
Gaseous Nitrogen ◽  
Optical Source ◽  
Shape Model ◽  
Induced Absorption ◽  
Close Frequency ◽  
Absorption Measurements

A (sub)millimetric source is obtained by difference-frequency mixing in a nonlinear crystal. It allows investigation of spectral absorption between 4 and 40 cm−1 with a new two-beam spectroscopic mounting. The complete mounting is described. The measurement method is given in detail. Compressed gaseous nitrogen-induced absorption measurements are used to calculate relaxation times and spectral moments. Comparisons are made with other measurements in close frequency regions, and theoretical models and an empirical line-shape model.

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