Vibrational relaxation in ground state p‐difluorobenzene: Single level preparation by stimulated emission pumping

1982 ◽  
Vol 77 (1) ◽  
pp. 570-571 ◽  
Author(s):  
Warren D. Lawrance ◽  
Alan E. W. Knight
Keyword(s):  
Ground State ◽  
Vibrational Relaxation ◽  
Stimulated Emission ◽  
Single Level

scholarly journals Singlet and Triplet Exciton Dynamics of Violanthrone

2021 ◽  
Author(s):  
Elham Gholizadeh ◽  
Shyamal Prasad ◽  
Lara Gillan ◽  
Dane R. McCamey ◽  
Murad J. Y. Tayebjee ◽  
...  
Keyword(s):  
Triplet State ◽  
Ground State ◽  
Density Functional ◽  
Transient Absorption ◽  
Density Functional Theory Calculations ◽  
Emission Feature ◽  
Stimulated Emission ◽  
Transient Absorption Spectrum ◽  
Exciton Dynamics ◽  
Solid Film

<div>The exciton dynamics of violanthrone-79 are investigated in solution and in the solid</div><div>state. In solution, the photo-prepared singlet is found to exhibit a strong ground-state bleach</div><div>and stimulated emission feature, but when sensitized in its triplet state, exhibits only a narrow</div><div>and weak ground-state bleach. As supported by density functional theory calculations,</div><div>this is explained by the triplet state having absorptions in the same region, with a similar</div><div>oscillator strength, as the ground state molecule. In solid films, the excited singlet is</div><div>found to survive only 100 ps, giving way to a long-lived transient absorption spectrum with</div><div>characteristics reminiscent of the triplet in solution. This is interpreted in terms of singlet</div><div>fission in the solid film.</div>

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.

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