Reverse ground-state excited-state transition dynamics in two-section quantum dot semiconductor lasers: mode-locking and state-switching

2010 ◽  
Author(s):  
Stefan Breuer ◽  
Mattia Rossetti ◽  
Wolfgang Elsässer ◽  
Lukas Drzewietzki ◽  
Paolo Bardella ◽  
...  
Keyword(s):  
Excited State ◽  
Quantum Dot ◽  
Semiconductor Lasers ◽  
Ground State ◽  
State Transition ◽  
Mode Locking ◽  
Transition Dynamics ◽  
State Switching

scholarly journals Power-induced lasing state switching and bistability in a two-state quantum dot laser subject to optical injection

2020 ◽  
Vol 50 (2) ◽  
Author(s):  
Zaifu Jiang ◽  
Zhengmao Wu ◽  
Elumalai Jayaprasath ◽  
Wenyan Yang ◽  
Chunxia Hu ◽  
...  
Keyword(s):  
Excited State ◽  
Quantum Dot ◽  
Ground State ◽  
The State ◽  
Optical Injection ◽  
State Switching ◽  
Quantum Dot Laser ◽  
Injection Power ◽  
Electron Escape ◽  
Free Running

We theoretically investigate power-induced lasing state switching and bistability in a two-state quantum dot laser subject to optical injection. The simulated results show that, for a free-running two-state quantum dot laser operating at the ground state under low current, a power-induced lasing state switching between the ground state and the excited state can be achieved through introducing optical injection with a frequency (winj) close to the lasing frequency of excited state (wES). The injection power required for the state switching depends on the scanning route of injection power, i.e. there may exist state bistability for the injection power within a certain region. For forward scanning injection power, with the increase of frequency detuning (ΔΩ = winj – wES), the injection power required for the state switching shows a decreasing trend accompanied by slight fluctuations. However, for backward scanning injection power, the injection power required for the state switching exhibits obvious fluctuations with the increase of ΔΩ. The width of the hysteresis loop fluctuates with ΔΩ, and the fluctuation amplitude is increased with the increase of the injection current. Additionally, the influences of the inhomogeneous broadening factor and the electron escape rate on the bistability performances are analyzed.

LIFETIME MEASUREMENTS OF STATES IN O18 AND Ne22

1964 ◽  
Vol 42 (6) ◽  
pp. 1311-1323 ◽  
Author(s):  
M. A. Eswaran ◽  
C. Broude
Keyword(s):  
Excited State ◽  
Ground State ◽  
Doppler Shift ◽  
State Transition ◽  
Branching Ratios ◽  
Ground State Transition ◽  
Lifetime Measurements ◽  
Doppler Shift Attenuation ◽  
First Excited State ◽  
Doppler Shift Attenuation Method

Lifetime measurements have been made by the Doppler-shift attenuation method for the 1.98-, 3.63-, 3.92-, and 4.45-Mev states in O18 and the 1.28-, 3.34-, and 4.47-Mev states in Ne22, excited by the reactions Li7(C12, pγ)O18 and Li7(O16, pγ)Ne22. Branching ratios have also been measured. The results are tabulated.[Formula: see text]The decay of the 3.92-Mev state in O18 is 93.5% to the 1.98-Mev state and 6.5% to the ground state and of the 4.45-Mev state 74% to the 3.63-Mev state, 26% to the 1.98-Mev state, and less than 2% to the ground state. In Ne22, the ground-state transition from the 4.47-Mev state is less than 2% of the decay to the first excited state.

scholarly journals Resonant photoluminescence and excitation spectroscopy of CdSe/ZnSe and CdTe/ZnTe self-assembled quantum dots

2002 ◽  
Vol 737 ◽  
Author(s):  
T. A. Nguyen ◽  
S. Mackowski ◽  
H. Rho ◽  
H. E. Jackson ◽  
L. M. Smith ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Excited State ◽  
Ground State ◽  
State Transition ◽  
Longitudinal Optical ◽  
Photoluminescence Spectra ◽  
Single Quantum Dots ◽  
Major Carrier ◽  
Excitation Mechanisms ◽  
Self Assembled

ABSTRACTWe show that two major carrier excitation mechanisms are present in II-VI self-assembled quantum dots. The first one is related to direct excited state – ground state transition. It manifests itself by the presence of sharp and intense lines in the excitation spectrum measured from single quantum dots. Apart from these lines, we also observe up to four much broader excitation lines. The energy spacing between these lines indicates that they are associated with absorption related to longitudinal optical phonons. By analyzing resonantly excited photoluminescence spectra, we are able to separate the contributions from these two mechanisms. In the case of CdTe dots, the excited state – ground state relaxation is important for all dots in ensemble, while phonon-assisted processes are dominant for the dots with smaller lateral size.

scholarly journals Emergence of resonant mode-locking via delayed feedback in quantum dot semiconductor lasers

2016 ◽  
Vol 24 (4) ◽  
pp. 4239 ◽  
Author(s):  
B. Tykalewicz ◽  
D. Goulding ◽  
S. P. Hegarty ◽  
G. Huyet ◽  
T. Erneux ◽  
...  
Keyword(s):  
Quantum Dot ◽  
Semiconductor Lasers ◽  
Resonant Mode ◽  
Mode Locking ◽  
Delayed Feedback

Excited state spectral blowup induced by carrier dynamics in the ground state of a quantum dot laser

2017 ◽  
Author(s):  
Bryan Kelleher ◽  
David Goulding ◽  
Boguslaw Tykalewicz ◽  
Stephen P. Hegarty ◽  
Ilya Dubinkin ◽  
...  
Keyword(s):  
Excited State ◽  
Quantum Dot ◽  
Ground State ◽  
Carrier Dynamics ◽  
Quantum Dot Laser

THE NEUTRON CAPTURE 7-RAYS FROM POTASSIUM

1953 ◽  
Vol 31 (6) ◽  
pp. 927-931 ◽  
Author(s):  
G. A. Bartholomew ◽  
B. B. Kinsey
Keyword(s):  
Excited State ◽  
Potassium Carbonate ◽  
Ground State ◽  
Neutron Capture ◽  
State Transition ◽  
Ground State Transition ◽  
Γ Rays ◽  
Γ Ray

The capture γ-rays from potassium have been re-examined with greater resolution than was used in previous experiments. The upper end of the spectrum has been carefully studied both with a sample of natural potassium carbonate and with another in which the potassium was enriched in K40. From a comparison of the spectra two γ-rays with energies of 9.39 ± 0.06 and 8.45 ± 0.02 Mev. are assigned to capture by that isotope. The strong γ-ray at 7.757 ± 0.008 Mev. previously ascribed to the ground state transition in K40 is now found to represent a transition to a low-lying excited state in that nucleus.

Shannon entropy and decoherence of bound magnetopolaron in a modified cylindrical quantum dot

2015 ◽  
Vol 29 (35n36) ◽  
pp. 1550241 ◽  
Author(s):  
A. J. Fotue ◽  
S. C. Kenfack ◽  
M. Tiotsop ◽  
N. Issofa ◽  
A. V. Wirngo ◽  
...  
Keyword(s):  
Excited State ◽  
Quantum Dot ◽  
Density Matrix ◽  
Shannon Entropy ◽  
Ground State ◽  
Superposition State ◽  
First Excited State ◽  
Coupling Strengths ◽  
The Magnetic Field ◽  
Bound Magnetopolaron

In this paper, we calculate the time evolution of the quantum mechanical state of a bound magnetopolaron in a modified cylindrical quantum dot. In the condition of strong coupling, we investigate the eigen energies and the eigenfunctions of the ground state and the first excited state, respectively. This system may be employed as a two-level quantum system qubit and therefore be helpful for storage of information. The Shannon entropy is used to investigate the decoherence of the qubit when the latter is in the superposition state of the ground and the first excited states. We also study the influence of the electric field, the magnetic field and the Coulomb potential on the decoherence time, eigen energies of the ground state, and the first excited state. It is shown that, the phonon spontaneous emission causes the decoherence of the qubit. We plot the decay of the density matrix of the qubit and the coherent term of the density matrix element [Formula: see text] (or [Formula: see text]) in a function of time for different coupling strengths, confinement lengths and dispersion coefficient.

scholarly journals Passive mode-locking of p-doped quantum dot semiconductor lasers

2020 ◽  
Vol 1695 ◽  
pp. 012068
Author(s):  
D Auth ◽  
V V Korenev ◽  
A V Savelyev ◽  
M V Maximov ◽  
A E Zhukov ◽  
...  
Keyword(s):  
Quantum Dot ◽  
Semiconductor Lasers ◽  
Mode Locking ◽  
Passive Mode
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