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Excitonic Gain Laser Action And The Role Of Many Body Effects In Znse Based Quantum Wells
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Book Synopsis Excitonic Gain, Laser Action, and the Role of Many-body Effects in ZnSe-Based Quantum Wells by : J. Ding
Download or read book Excitonic Gain, Laser Action, and the Role of Many-body Effects in ZnSe-Based Quantum Wells written by J. Ding and published by . This book was released on 1992 with total page 6 pages. Available in PDF, EPUB and Kindle. Book excerpt: Among potential applications of wide-gap II-VI compound semiconductor quantum wells (QW) and superlattices at short visible wavelengths are lasers and nonlinear optical devices. Substantial progress has been recently made with ZnSe-based heterostructures; in particular (Zn, Cd)Se/ZnSe QW's have shown pulsed room temperature laser action in optical pumping experiments in both multiple and single well structures. At the same time, these QW's have also been found to display strong excitonic absorption features (a> 10(5) cm-1), which are well preserved up to room temperature and beyond. This raises the question about the origin of the gain for lasers, that is, the role of Coulomb effects when compared to the usual inversion from an electron-hole plasma encountered e.g. in GaAs quantum well lasers. Here we show initial results of pump-probe experiments and laser studies which indicate the presence of excitonic gain up to temperatures at least as high as 200 K. Moreover, with increasing pair density, the gain evolves directly from saturation of the excitonic gain in the (Zn, Cd)Se/ZnSe quantum wells.
Book Synopsis Excitonic Gain and Laser Action in ZnSe Based Quantum Confined Structures by : Jian Ding
Download or read book Excitonic Gain and Laser Action in ZnSe Based Quantum Confined Structures written by Jian Ding and published by . This book was released on 1992 with total page 252 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Exciton Effects in Zinc Selenide Based Multiple Quantum Well Lasers and Modulators by : Wenli Huang
Download or read book Exciton Effects in Zinc Selenide Based Multiple Quantum Well Lasers and Modulators written by Wenli Huang and published by . This book was released on 1995 with total page 234 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Quantum Well Lasers by : Peter S. Zory
Download or read book Quantum Well Lasers written by Peter S. Zory and published by Academic Press. This book was released on 1993-04-13 with total page 530 pages. Available in PDF, EPUB and Kindle. Book excerpt: Provides information on all aspects of QW lasers, from the basic mechanism of optical gain, through the current technological state of the art, to the future technologies of quantum wires and quantum dots. Those working with lasers, especially semiconductor lasers, should find the book useful.
Book Synopsis Spatially Indirect Excitons in Coupled Quantum Wells by : Chih-Wei Eddy Lai
Download or read book Spatially Indirect Excitons in Coupled Quantum Wells written by Chih-Wei Eddy Lai and published by . This book was released on 2004 with total page 362 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Physics of Strained Quantum Well Lasers by : John P. Loehr
Download or read book Physics of Strained Quantum Well Lasers written by John P. Loehr and published by Springer Science & Business Media. This book was released on 1997-12-31 with total page 282 pages. Available in PDF, EPUB and Kindle. Book excerpt: When this publisher offered me the opportunity to \\Tite a book, some six years ago, I did not hesitate to say yes. I had just spent the last four years of graduate school struggling to understand the physics of strained quantum well lasers, and it seemed to me the whole experience was much more difficult that it should have been. For although many of the results I needed were easy to locate, the underlying physical premises and intervening steps were not. If only I had a book providing the derivations, I could have absorbed them and gone on my way. Such a book lies before you. It provides a unified and self-contained descrip tion of the essential physics of strained quantum well lasers, starting from first principles whenever feasible. The presentation I have chosen requires only the standard introductory background in quantum mechanics, solid state physics, and electromagnetics expected of entering graduate students in physics or elec trical engineering. A single undergraduate course in each of these subjects should be more than sufficient to follow the text. :'Iore advanced material on quantum mechanics is developed and collected in the first chapter. \Vhen pos sible, I have presented the results in a general setting and have later applied them to specific cases of interest. I find this the most satisfying way to ap proach the subject, and it has the additional benefit of solving many problems once and for all.
Book Synopsis A many-body theory for laser emission and excitonic effects in semiconductor microcavities by : Frank Jahnke
Download or read book A many-body theory for laser emission and excitonic effects in semiconductor microcavities written by Frank Jahnke and published by . This book was released on 1996 with total page 161 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Exciton Dynamics in AlGaAs/GaAs Quantum Wells and in Focused Ion Beam Patterned Quantum Well Wire-like Structures by : Xuelong Cao
Download or read book Exciton Dynamics in AlGaAs/GaAs Quantum Wells and in Focused Ion Beam Patterned Quantum Well Wire-like Structures written by Xuelong Cao and published by . This book was released on 1995 with total page 250 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Gain Spectroscopy and Device Physics of ZnSe Based Quantum Well Heterostructures by : Mary M. Hagerott
Download or read book Gain Spectroscopy and Device Physics of ZnSe Based Quantum Well Heterostructures written by Mary M. Hagerott and published by . This book was released on 1994 with total page 322 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Excitonic Binding Energies in Quantum Wells by : Joachim Wüsthoff
Download or read book Excitonic Binding Energies in Quantum Wells written by Joachim Wüsthoff and published by . This book was released on 1998 with total page 141 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Dynamics of Excitons in Quantum Wells by : M. Zachau
Download or read book Dynamics of Excitons in Quantum Wells written by M. Zachau and published by . This book was released on 1992 with total page 4 pages. Available in PDF, EPUB and Kindle. Book excerpt: We measure the time dependence of the excitonic photoluminescence (PL) in quantum wells (QWs) with well width Lz ranging from 25A to 50A. The samples are AI0.2Ga0.8As/GaAs multiple QWs with 30 periods with decoupled wells and were grown by molecular beam epitaxy (MBE). QWs grown with and without growth interruption at the interfaces are investigated. The excitation is provided by 5 psec pulses from a synchronously pumped tunable dye laser. The PL spectrum is detected by an imaging (i.e. multichannel) photomultiplier with a spectral resolution of 0.5 meV and time resolution (FWHM) of 120 psec.
Book Synopsis Novel Electric-Field Effects in Quantum Wells, Superlattices, and Microcavities by :
Download or read book Novel Electric-Field Effects in Quantum Wells, Superlattices, and Microcavities written by and published by . This book was released on 2000 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: We have used an external electric field to control important properties of semiconductor quantum wells. Specifically: (1) We have modified the exciton-exciton interaction. This interaction is determined by many-body effects, which depend on the overlap between the exciton's electron and hole wavefunctions, and is manifested in the energy difference between photoluminescence spectra with different polarizations. In time-resolved photoluminescence (PL) experiments with circular polarization we have observed that spectral difference, which we controlled by an electric field applied to GaAs-GaAlAs coupled quantum wells. Our results confirm the predictions of theory but also point out its limitations to fully explain our observations. (2) We have reversed the valence-band ordering in strained-layer quantum wells, thus 'undoing' the effects of strain. To prove the concept we have used strained InGaAs-InAlAs quantum wells in which the light-hole state is the ground state in the valence band. Photocurrent measurements under various fields have shown a change in the valence-band states that contribute to the fundamental (lowest-energy) transition, from light-hole states to heavy-hole states. This result opens the door to reversing the polarization of light emission in quantum wells, from TM to TE, which could find application in optical modulators. (3) We have shown the presence of low-temperature exciton-photon coupling in microcavities using PL spectroscopy. Because of thermalization until now it has been almost impossible to use PL to study at low temperature (T = 20K or less) the coupling of excitons and photons. We have determined the difference between the lowest-energy PL peak from a quantum well-microcavity system and that of an isolated quantum well, at various temperatures. This difference is constant with T when a field is applied but is T dependent when the field is suppressed. The maximum variation is a direct measure of the exciton-photon coupling.
Book Synopsis Dephasing of Excitons and Phase Coherent Photorefractivity in ZnSe Quantum Wells by : Suvranta K. Tripathy
Download or read book Dephasing of Excitons and Phase Coherent Photorefractivity in ZnSe Quantum Wells written by Suvranta K. Tripathy and published by . This book was released on 2006 with total page 140 pages. Available in PDF, EPUB and Kindle. Book excerpt: Spectrally resolved and time-integrated degenerate four-wave mixing (FWM) experiments with ultra-short pulses have been used to investigate the relaxation times and coherent interactions of excitons in the Boltzmann and in the quantum kinetic regime in ZnSe single quantum wells (QWs). The interband and interexciton coherences has been investigated in three-pulse FWM experiments using 100 fs pulses in a 10 nm ZnSe QWs. The FWM signals obtained in three-beam FWM experiment are explained by optical Bloch equations (OBEs) for a ten-level model including excitation induced dephasing (EID). Two-beam FWM experiments using 30 fs pulses on a 10 nm ZnSe quantum well reveal marked quantum beats and a pronounced non-exponential decay for delay times smaller ~500 fs. The three-beam FWM trace shows a bi-exponential decay which is attributed to a nonlinear polarization that is caused by the interaction of polarization of third beam with both an exciton grating and an eh-pair grating. Model calculations using the OBEs of a two level system that includes EID at both types of density grating provide information about exciton formation processes involved. We observe coherent exciton-LO-phonon polarons in the FWM spectrum of a 3 nm ZnSe single quantum well using 30 fs pulses. The formation of the new quasi-particles is attributed to a strong phonon coupling that is caused by strong Frohlich interaction, a huge exciton binding that exceeds the LO-phonon energy and a close resonance between the 2s exciton state and LO-phonon energy. The rapid decay of these coherent quasiparticles is attributed to the disintegration into zero-phonon excitons and free LO-phonons as well as to the inhomogeneous broadening of LO-phonon energies due to disorder and k-space dispersion A novel phase coherent photorefractive (PCP) effect has been observed in ZnSe single QWs using ultra-short pulses that do not overlap in time and its spectral and thermal dependence have been investigated. The observed PCP effect is attributed to the formation of an electron grating formed by the interference of coherent excitons. The experimental results are reproduced by OBEs for a five-level system.
Book Synopsis Advances In Semiconductor Lasers And Applications To Optoelectronics (Ijhses Vol. 9 No. 4) by : Mitra Dutta
Download or read book Advances In Semiconductor Lasers And Applications To Optoelectronics (Ijhses Vol. 9 No. 4) written by Mitra Dutta and published by World Scientific. This book was released on 2000-06-21 with total page 447 pages. Available in PDF, EPUB and Kindle. Book excerpt: Foreword by Charles H Townes This volume includes highlights of the theories underlying the essential phenomena occurring in novel semiconductor lasers as well as the principles of operation of selected heterostructure lasers. To understand scattering processes in heterostructure lasers and related optoelectronic devices, it is essential to consider the role of dimensional confinement of charge carriers as well as acoustical and optical phonons in quantum structures. Indeed, it is important to consider the confinement of both phonons and carriers in the design and modeling of novel semiconductor lasers such as the tunnel injection laser, quantum well intersubband lasers, and quantum dot lasers. The full exploitation of dimensional confinement leads to the exciting new capability of scattering time engineering in novel semiconductor lasers.As a result of continuing advances in techniques for growing quantum heterostructures, recent developments are likely to be followed in coming years by many more advances in semiconductor lasers and optoelectronics. As our understanding of these devices and the ability to fabricate them grow, so does our need for more sophisticated theories and simulation methods bridging the gap between quantum and classical transport.
Book Synopsis Laser Spectroscopy of Quantum Well and Superlattice Structures by :
Download or read book Laser Spectroscopy of Quantum Well and Superlattice Structures written by and published by . This book was released on 1990 with total page 34 pages. Available in PDF, EPUB and Kindle. Book excerpt: The potential for tailoring band structures of semiconductors with specific properties using molecular beam epitaxy (MBE) and metallorganic chemical vapour deposition (MOCVD) has considerable significance for future electronic and optoelectronic devices. These techniques permit the growth of structure with alternating layers of two semiconductors on top of each other which have band structures that alternate with characteristic peridocity (Fig. 1b) giving a one-dimensional Kronig-Penney structure. Superlattices are grown with well widths ranging from 1-50nm with rather thicker barriers. Electrons and holes are confined in the potential wells in the conduction and valence bands respectively. The transition rates of these excitonic luminescence processes should be given by the inverse of the radiative lifetime, tau sub R, leading to a homogeneous linewidth Delta omega = 1/tau sub R. At low temperature the exciton linewidth for a typical 5.0nm well in GaAs is about 100 times larger than in bulk material, which is already inhomogeneously broadened by the effects of strain. Obviously the exciton luminescence line experiences an additional inhomogeneous broadening which dominates the experimental linewidth.
Book Synopsis Electric Field Dependent Absorption of ZnSe-based Quantum Wells and Application to Optically Bistable Devices by : Detlef Merbach
Download or read book Electric Field Dependent Absorption of ZnSe-based Quantum Wells and Application to Optically Bistable Devices written by Detlef Merbach and published by . This book was released on 1998 with total page 145 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Many-body Effects in Metals, Modulation Doped Quantum Wells and Doped Semiconductors by : Ilias Perakis
Download or read book Many-body Effects in Metals, Modulation Doped Quantum Wells and Doped Semiconductors written by Ilias Perakis and published by . This book was released on 1992 with total page 258 pages. Available in PDF, EPUB and Kindle. Book excerpt: A new approach to the problem of X-ray edge singularities and peaks of many-body origin observed in the optical spectra is presented. We first establish the analogy between a system of one hole interacting with many electrons and the polaron, where one electron interacts with many phonons. We approach both cases as an eigenvalue problem for the time independent Schrodinger equation, obtain expressions for the many-body eigenstates in a convenient basis and use them to understand the behavior of the system. In the case of a localized hole with infinite mass, we diagonalize the Hamiltonian exactly using first a wavefunction and then a noncanonical transformation technique. We use the expressions for the eigenstates to obtain the exact analytic formulas for the optical spectra, accurate over the whole frequency range. We then apply our techniques to the case of a finite mass valence hole, which is realized in modulation doped quantum wells or wires. In this case we approximately diagonalize the Hamiltonian by treating exactly the most important terms leading to nonperturbative behavior. The terms neglected are identified and can be treated in perturbation theory. Our method provides a clear physical picture and valuable insight into the accurate treatment of many-body Hamiltonians.
