Stimulated emission in aluminum laser-induced plasma: kinetic model of population inversion

The technique of photoluminescence (PL) studies based on intense picosecond excitation of electron–hole pairs is applied to investigate the electron energy structure including the positions of high-lying excited levels in stepped quantum wells (QWs). The spectra of PL in regimes of spontaneous and stimulated emission are studied under different excitation levels and light polarizations. Of special interest are intense photoluminescence signals from excited subbands. The feasibility of a e3–e2 intersubband population inversion in stepped QWs is demonstrated and the influence of Auger recombination was examined.

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Spontaneous and Stimulated Intersubband Emission Under Optical Pumping

MRS Proceedings ◽

10.1557/proc-450-111 ◽

1996 ◽

Vol 450 ◽

Cited By ~ 1

Author(s):

P. Boucaud ◽

S. Sauvage ◽

O. Gauthier-Lafaye ◽

Z. Moussa ◽

F.-H. Julien ◽

...

Keyword(s):

Quantum Wells ◽

Free Electron Laser ◽

Population Inversion ◽

Laser Emission ◽

Optical Pumping ◽

Stimulated Emission ◽

Mid Infrared ◽

Asymmetric Quantum ◽

Waveguide Length ◽

Subband Energy

ABSTRACTWe have investigated the mid-infrared spontaneous and stimulated emission between confined subbands in the conduction band of GaAs/AlGaAs quantum wells. The carriers which give rise to the intersubband emission are excited in the upper subbands using an intersubband optical pumping in coupled asymmetric quantum wells. The quantum wells are designed using phonon engineering in order to obtain population inversion between the second and first excited subband. This is obtained by adjusting the subband energy spacing between E2 and E1 close to the optical phonon energy which in turn allows an efficient relaxation. We have first observed intersubband spontaneous emission between E3 and E2 at 14 μm using an intersubband pumping with a CO2 laser in resonance with the E1-E3 transition. In a second set of experiments, the quantum wells are embedded in an infrared waveguide. We have measured the stimulated intersubband gain using a picosecond two-color free electron laser. The first color bleaches the E1-E3 transition and provides the population inversion. The intersubband stimulated gain is measured versus the waveguide length and photon energy. Stimulated gains ≈ 80 cm−1 are reported thus demonstrating that laser emission under optical pumping appears feasible in optimized structures. Finally, we show that intersubband emission can also be observed in quantum wells using an interband optical pumping.

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Химический сдвиг и энергия обменного взаимодействия 1s состояний доноров магния в кремнии. Возможность стимулированного излучения

Физика и техника полупроводников ◽

10.21883/ftp.2019.09.48135.18 ◽

2019 ◽

Vol 53 (9) ◽

pp. 1263

Author(s):

В.Н. Шастин ◽

Р.Х. Жукавин ◽

К.А. Ковалевский ◽

В.В. Цыпленков ◽

В.В. Румянцев ◽

...

Keyword(s):

Experimental Data ◽

Population Inversion ◽

Elevated Temperatures ◽

Stimulated Raman Scattering ◽

Stimulated Emission ◽

Fano Resonances ◽

Relaxation Rates ◽

Specific Mechanism ◽

S States ◽

Mg Doped

AbstractThe results of experiments aimed at the observation of split 1 s states in Mg-doped Si are reported. From the results, it is possible to determine the chemical shift and exchange interaction energy of a neutral Mg donor in Si. The position of the 1 s ( E ), 1 s ( T _2), and 2 s ( A _1) parastates determines the possibility for attaining population inversion and the specific mechanism of stimulated Raman scattering. The energy of the 1 s ( T _2) parastate is determined from the position of the Fano resonances in the photoconductivity spectrum of Si:Mg at T = 4 K, and the energies of the 1 s ( T _2) and 1 s ( E ) orthostates from the transmittance spectra at elevated temperatures. On the basis of the experimental data, the relaxation rates are estimated, and the possible mechanisms of stimulated emission are analyzed.

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Kinetic model of titanium laser induced plasma expansion in nitrogen environment

Plasma Sources Science and Technology ◽

10.1088/0963-0252/18/2/025027 ◽

2009 ◽

Vol 18 (2) ◽

pp. 025027 ◽

Cited By ~ 17

Author(s):

A R Casavola ◽

G Colonna ◽

M Capitelli

Keyword(s):

Kinetic Model ◽

Plasma Expansion ◽

Laser Induced Plasma

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Kinetics of Laser Induced Plasma on an Aqueous Surface

Laser Chemistry ◽

10.1080/02786270215154 ◽

2002 ◽

Vol 20 (2-4) ◽

pp. 123-134 ◽

Cited By ~ 10

Author(s):

J. Ben Ahmed ◽

Z. Ben Lakhdar ◽

G. Taieb

Keyword(s):

Kinetic Model ◽

Laser Pulse ◽

Aqueous Solutions ◽

Emission Spectra ◽

Electron Recombination ◽

Time Resolved ◽

Temporal Shift ◽

Laser Induced Plasma ◽

Aqueous Surface ◽

Kinetics Of

Emission spectra of MgI and MgII from a plasma induced by the interaction of a laser pulse with the surface of aqueous solutions of MgCl2, were recorded by a time resolved spectroscopy method to obtain information on the processes involved in the formation and the evolution of the two different species. A kinetic model based on ion-electron recombination produced during the relaxation of the plasma is constructed with the aim to explain the origin and the temporal shift of observed Mg+ and Mg emissions. Comparison with the experimental results is presented and discussed.

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Mirrorless Lasing in Liquid Crystalline Photonic Bandgap Materials

MRS Proceedings ◽

10.1557/proc-776-q9.7 ◽

2003 ◽

Vol 776 ◽

Cited By ~ 1

Author(s):

Wenyi Cao ◽

Antonio Muñoz ◽

Peter Palffy-Muhoray ◽

Bahman Taheri

Keyword(s):

Population Inversion ◽

Liquid Crystalline ◽

Light Propagation ◽

Photonic Bandgap ◽

Photon Counting ◽

Stimulated Emission ◽

Photonic Bandgap Materials ◽

Blue Phase ◽

Counting Statistics ◽

Applied Fields

AbstractLiquid crystals (LC) are promising photonic bandgap (PBG) materials. Certain LC phases have spatially modulated ground states and effectively form self-assembled PBG structures. These structures can also be made permanent by photopolymerization. Typically, LCs respond readily to applied fields, enabling modulation and switching of the bandgap. Since classical light propagation is forbidden, fluorescent emission in the band gap can lead to population inversion and stimulated emission at the band edges. Mirrorless lasing experiments provide an effective probe of the bandgap. We discuss the underlying physics, and present the results of mirrorless lasing in a variety of cholesteric LC materials, including recent results of photon counting statistics and 3-D lasing in the cholesteric blue phase.

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