scholarly journals Femtosecond pump-probe spectroscopy of intersubband relaxation dynamics in narrow InGaAs∕AlAsSb quantum well structures

2006 ◽  
Vol 89 (17) ◽  
pp. 171104 ◽  
Author(s):  
C. V.-B. Tribuzy ◽  
S. Ohser ◽  
S. Winnerl ◽  
J. Grenzer ◽  
H. Schneider ◽  
...  
Keyword(s):  
Quantum Well ◽  
Relaxation Dynamics ◽  
Pump Probe ◽  
Quantum Well Structures ◽  
Probe Spectroscopy ◽  
Intersubband Relaxation

scholarly journals lntersubband Relaxation in Step Quantum Well Structures

VLSI Design ◽  
1998 ◽  
Vol 8 (1-4) ◽  
pp. 289-293
Author(s):  
J. P. Sun ◽  
H. B. Teng ◽  
G. I. Haddad ◽  
M. A. Stroscio ◽  
G. J. Iafrate
Keyword(s):  
Quantum Well ◽  
Form Factors ◽  
Phonon Energy ◽  
Longitudinal Optical Phonon ◽  
Relaxation Rates ◽  
Phonon Modes ◽  
Quantum Well Structures ◽  
Bulk Phonon ◽  
Interface Phonons ◽  
Intersubband Relaxation

Intersubband relaxation due to electron interactions with the localized phonon modes plays an important role for population inversion in quantum well laser structures designed for intersubband lasers operating at mid-infrared to submillimeter wavelengths. In this work, intersubband relaxation rates between subbands in step quantum well structures are evaluated numerically using Fermi's golden rule, in which the localized phonon modes including the asymmetric interface modes, symmetric interface modes, and confined phonon modes and the electron – phonon interaction Hamiltonians are derived based on the macroscopic dielectric continuum model, whereas the electron wave functions are obtained by solving the Schrödinger equation for the heterostructures under investigation. The sum rule for the relationship between the form factors of the various localized phonon modes and the bulk phonon modes is examined and verified for these structures. The intersubband relaxation rates due to electron scattering by the asymmetric interface phonons, symmetric interface phonons, and confined phonons are calculated and compared with the relaxation rates calculated using the bulk phonon modes and the Fröhlich interaction Hamiltonian for step quantum well structures with subband separations of 36 meV and 50meV, corresponding to the bulk longitudinal optical phonon energy and interface phonon energy, respectively. Our results show that for preferential electron relaxation in intersubband laser structures, the effects of the localized phonon modes, especially the interface phonon modes, must be included for optimal design of these structures.

Quasiparticle relaxation dynamics in underdoped Bi2Sr2CaCu2O8+δby two-color pump-probe spectroscopy

2011 ◽  
Vol 84 (17) ◽  
Author(s):  
Y. Toda ◽  
T. Mertelj ◽  
P. Kusar ◽  
T. Kurosawa ◽  
M. Oda ◽  
...  
Keyword(s):  
Relaxation Dynamics ◽  
Pump Probe ◽  
Quasiparticle Relaxation ◽  
Probe Spectroscopy

Direct observation of intersubband relaxation in narrow multiple quantum well structures

1988 ◽  
Vol 31 (3-4) ◽  
pp. 767-770 ◽  
Author(s):  
A. Seilmeier ◽  
H.-J. Hübner ◽  
M. Wörner ◽  
G. Abstreiter ◽  
G. Weimann ◽  
...  
Keyword(s):  
Quantum Well ◽  
Direct Observation ◽  
Multiple Quantum Well ◽  
Multiple Quantum ◽  
Quantum Well Structures ◽  
Intersubband Relaxation

scholarly journals Orbital-Dependent Photodynamics of Strongly Correlated Clusters

2021 ◽  
Author(s):  
Jacob Garcia ◽  
Scott Sayres
Keyword(s):  
Theoretical Calculations ◽  
Advanced Materials ◽  
Strongly Correlated ◽  
Relaxation Dynamics ◽  
Pump Probe ◽  
Defect Sites ◽  
Atomic Precision ◽  
Bulk Scale ◽  
Probe Spectroscopy

Understanding the role of defect sites on the mechanism and lifetime of photoexcited state relaxation is critical for the ration-al design of advanced materials. Here, the ultrafast electronic relaxation dynamics of neutral nickel oxide clusters were inves-tigated with femtosecond pump-probe spectroscopy and supported with theoretical calculations to reveal that their excited state lifetimes are strongly dependent on the nature of the electronic transition. Absorption of a UV photon produces short lived (lifetime ~110 fs) dynamics in stoichiometric (NiO)n clusters (n < 6) that are attributed to a ligand to metal charge transfer (LMCT) and produces metallic-like electron-electron scattering. Oxygen vacancies introduce excitations with Ni-3d→Ni-4s and 3d→4p character, which increases the lifetimes of the sub-picosecond response by up to 80% and enables the formation of long-lived (lifetimes > 2.5 ps) states. The atomic precision and tunability of gas phase clusters are employed to highlight a unique reliance on the Ni orbital contributions to the photoexcited lifetimes, providing new insights to the anal-ogous band edge excitation dynamics of strongly correlated bulk-scale NiO materials.

Femtosecond Pump and Probe Spectroscopy on Poly(Para-Phenylenes)

1997 ◽  
Vol 488 ◽  
Author(s):  
W. Graupner ◽  
G. Cerullo ◽  
G. Kranzelbinder ◽  
G. Lanzani ◽  
S. Stagira ◽  
...  
Keyword(s):  
Stimulated Emission ◽  
Excitation Density ◽  
Relaxation Dynamics ◽  
Additional Absorption ◽  
Pump Probe ◽  
Band Emission ◽  
Decay Component ◽  
Pump And Probe ◽  
Ladder Polymer ◽  
Probe Spectroscopy

AbstractWe studied the sub-picosecond dynamics of photoexcitations in methyl-substituted poly(para--phenylene)-type ladder polymer (m-LPPP) films in a wide excitation density range up to values typical for the regime of narrow band emission by pump-probe spectroscopy. The singlet excitons relaxation dynamics, monitored at the stimulated emission (SE) peak at 2.53 eV, showed an intensity dependent ultrafast decay component, which occurs on a sub-picosecond time scale, ascribed to the onset of amplified spontaneous emission (ASE). In addition we identified photoinduced absorption (PA) bands of singlet excitons at 1.48 eV and polarons at 1.9 eV respectively. At high excitation density an additional absorption band becomes evident at 2.63 eV.

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