Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

Conference on Lasers and Electro-Optics

Observation of electron-hole plasma via exciton Mott transition in CuCl by mid-infrared pump probe spectroscopy

Masaya Nagai, Masaaki Ashida, Ryo Shimano, Makoto Kuwata‐Gonokami

Published Aug 29, 2005• 0 citations
Publisher

Abstract

Summary form only given. Temperature in direct-gap semiconductor show collective quantum mechanical effects such as the formation of electron-hole liquid and exciton condensation. In the usual band to band excitation, the initial temperature of the carriers remains high within their lifetime. However, creating electron-hole pairs via exciton Mott transition can a good system to realize such a transition, because of its large (213 meV) is Z/sub 3/ exciton binding energy. Recently we have reported on the observation of broad band emission at 100 meV below the exciton band for resonant exciton excitation in CuCl. We perform pump probe measurements in the mid-infrared region in order to understand the origin of the emission band. If high density excitons form plasma, change in reflectivity, increase below plasma frequency and decreases above plasma frequency.

DOI
10.1109/iqec.2000.907873

Related papers

Optical transitions from the lowest to higher exciton and biexciton Rydberg states in CuCl

Kensuke Miyajima, K. Sakaniwa, M. Sugawara

We measured the optical transitions due to the internal energy levels of an exciton and biexciton in a CuCl single crystal using pump-probe spectroscopy. The transient absorption bands due to the transitions from the $1s$ to $2p$ and from the $1s$ to $3p$ exciton states were observed at 3 K, which is consistent with their reported energies. Simultaneously, the transient absorption peak due to the biexciton was observed, which corresponds to a transition from the lowest state (composed of two $1s$ excitons) to higher states (composed of $1s$ and $2p$ excitons). The value of the observed biexciton peak energy was reasonable considering the hydrogen molecule orbitals and the electron-to-hole effective mass ratio. In addition, the transient absorption peaks were broadened at 77 K, because of the increase in the homogeneous width of the $2p$ exciton state. The transient absorption spectrum was almost completely determined by this width. Our findings are of importance with regard to the optical phenomena in the infrared region related to the quantum coherence of excitons and biexcitons in semiconductors.

Physical review. B./Physical review. B•Nov 28, 2016•4 citations

Observation of optical Stark effect between 1s - 2p exciton levels in CuCl single crystal

S Efumi, Yuki Uchibori, Jun Ishihara +1 more

We measured the transient reflection spectra induced by infrared light for a CuCl single crystal using pump-probe spectroscopy. A Stark shift of the 1 s exciton was observed using light with a near resonant energy between the 1 s and 2 p exciton levels. The amount of energy shift due to the Stark effect was obtained from the absorption spectra calculated using the Kramers–Kronig transform. We investigated the energy shift of 1 s excitons with respect to the excitation density. This is the first published report on the Stark effect of 1 s exciton associated with the internal energy levels of the excitons in CuCl crystal.

Journal of Physics Conference Series•May 1, 2019•3 citations

Photoluminescence of quantum-confined semiconductor structures

Sorin Mosor

Different aspects of the photoluminescence from semiconductor quantum-confined structures are studied in this dissertation, for a better understanding of fundamental physics of semiconductors.The precursor of any photoluminescence study is the characterization of the linear optical properties of the semiconductor structure. High resolution absorption measurements were performed in order to study the interplay of disorder and acoustic phonon scattering in a quantum well. Also, reflectivity measurements, together with a fitting procedure based on the transfer matrix formalism, are used to determine the thickness of samples.Excitons are atom-like quasi-particles, formed from a bound electron-hole pair. They follow a Bose-Einstein statistic, so in principle it is possible to achieve an excitonic Bose-Einstein condensate. Time resolved photoluminescence measurements were performed over an extensive range of lattice temperatures and carrier concentrations, in order to determine the fraction of excitons formed from the electron-hole plasma in a quantum well, after non-resonant excitation. The experimental spectra were compared to a pure plasma calculation first, then excitons were taken into account. The highest fraction of formed excitons is found for low temperatures and intermediate carrier densities. This fraction is found to be very small, and this has clear implications on the excitonic Bose-Einstein condensation studies.The photoluminescence emitted left and right from a quantum well is interfered in a modified Mach-Zender interferometer. It is shown that the light emitted on the two paths will interfere for a V-shape geometry and will not for any other paths.A structure formed by placing a quantum well in a field antinode of a resonant planar microcavity exhibits normal mode coupling: splitting of the resonance spectral line. The coherence properties of the photoluminescence from a normal-mode-coupling microcavity are studied using another version of the Mach-Zender interferometer. The degree of coherence measured in this way depends greatly on the pump wavelength and intensity, ranging from zero to 0.8. However, direct observation of the emission speckle shows significant coherence in all cases. The difference is explained by the different methods used to evaluate the coherence.The strong coupling between a quantum dot and a photonic crystal nanocavity is investigated by observation of photoluminescence. A new method of tunning the cavity wavelength by deposition of a thin film of solid Xenon on all the surfaces of the sample is presented. The method allows the scanning of the cavity wavelength with about 5 nm without a decrease in the quality factor and without changing the temperature.Finally, an extensive study of the quality factors of quantum dot photonic crystal nanocavities is presented. The role of the quantum dot ensemble absorption is investigated. At higher excitation levels, lasing is observed and discussed.

•Jan 1, 2005•0 citations

Polaritonic Stop-Band Transparency via Exciton-Biexciton Coupling in CuCl

Stefano Chesi, M. Artoni, Giuseppe Carlo La Rocca +2 more

Radiation is almost completely reflected within the exciton-polariton stop band of a semiconductor, as in the typical case of CuCl. We predict, however, that a coherently driven exciton-biexciton transition allows for the propagation of a probe light beam within the stop band. The phenomenon is reminiscent of electromagnetically induced transparency effects occurring in three-level atomic systems, except that it here involves delocalized electronic excitations in a crystalline structure via a frequency and wave-vector selective polaritonic mechanism. A well-developed transparency, favored by the narrow linewidth of the biexciton, is established within the stop band where a probe pulse may propagate with significant delays. The transparency window can be controlled via the pump beam detuning and intensity.

Physical Review Letters•Jul 29, 2003•23 citations

Nonlinear behaviour of the resonance fluorescence from excitons in quantum wells

G. K. G. Burau, Günter Manzke, Frank Kieseling +3 more

We examine the resonance fluorescence from localized excitons in GaAs/AlGaAs quantum wells with increasing excitation power and for different temperatures. Extending our experimental setup by a microscope objective with high numerical aperture in the cryostat, the detection of the emission from localized excitons is possible. We find a nonlinear behaviour of the emitted intensity with increasing laser power, which is explained as a transition of the emission from excitonic to electron-hole plasma states due to many-body effects between excited carriers. This is supported by our theoretical description based on the semiconductor Bloch equations.

Journal of Physics Conference Series•Feb 1, 2010•3 citations

Exciton–biexciton quantum coherence and polaritonic stop‐band transparency in CuCl

Stefano Chesi, M. Artoni, Giuseppe Carlo La Rocca +2 more

A coherently driven exciton–biexciton transition in CuCl enables one to propagate a probe light beam within the exciton-polariton stop-band where radiation is otherwise completely reflected. The stop-band transparency window can be controlled via the pump beam frequency and intensity. The phenomenon is reminiscent of quantum coherence effects occurring in three-level atomic systems, except that it here involves delocalized electronic excitations in a crystal via a frequency and wave-vector selective polaritonic mechanism. Both a free standing slab and a microcavity configuration are theoretically studied. (© 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

Physica status solidi. C, Conferences and critical reviews/Physica status solidi. C, Current topics in solid state physics•Feb 1, 2004•1 citation
Summary form only given. Temperature in direct-gap semiconductor show collective quantum mechanical effects such as the formation of electron-hole liquid and exciton condensation. In the usual band to band excitation, the initial temperature of the carriers remains high within their lifetime. However, creating electron-hole pairs via exciton Mott transition can a good system to realize such a transition, because of its large (213 meV) is Z/sub 3/ exciton binding energy. Recently we have reported on the observation of broad band emission at 100 meV below the exciton band for resonant exciton excitation in CuCl. We perform pump probe measurements in the mid-infrared region in order to understand the origin of the emission band. If high density excitons form plasma, change in reflectivity, increase below plasma frequency and decreases above plasma frequency.
We measured the optical transitions due to the internal energy levels of an exciton and biexciton in a CuCl single crystal using pump-probe spectroscopy. The transient absorption bands due to the transitions from the 1s1s1s to 2p2p2p and from the 1s1s1s to 3p3p3p exciton states were observed at 3 K, which is consistent with their reported energies. Simultaneously, the transient absorption peak due to the biexciton was observed, which corresponds to a transition from the lowest state (composed of two 1s1s1s excitons) to higher states (composed of 1s1s1s and 2p2p2p excitons). The value of the observed biexciton peak energy was reasonable considering the hydrogen molecule orbitals and the electron-to-hole effective mass ratio. In addition, the transient absorption peaks were broadened at 77 K, because of the increase in the homogeneous width of the 2p2p2p exciton state. The transient absorption spectrum was almost completely determined by this width. Our findings are of importance with regard to the optical phenomena in the infrared region related to the quantum coherence of excitons and biexcitons in semiconductors.
We measured the transient reflection spectra induced by infrared light for a CuCl single crystal using pump-probe spectroscopy. A Stark shift of the 1 s exciton was observed using light with a near resonant energy between the 1 s and 2 p exciton levels. The amount of energy shift due to the Stark effect was obtained from the absorption spectra calculated using the Kramers–Kronig transform. We investigated the energy shift of 1 s excitons with respect to the excitation density. This is the first published report on the Stark effect of 1 s exciton associated with the internal energy levels of the excitons in CuCl crystal.
Different aspects of the photoluminescence from semiconductor quantum-confined structures are studied in this dissertation, for a better understanding of fundamental physics of semiconductors.The precursor of any photoluminescence study is the characterization of the linear optical properties of the semiconductor structure. High resolution absorption measurements were performed in order to study the interplay of disorder and acoustic phonon scattering in a quantum well. Also, reflectivity measurements, together with a fitting procedure based on the transfer matrix formalism, are used to determine the thickness of samples.Excitons are atom-like quasi-particles, formed from a bound electron-hole pair. They follow a Bose-Einstein statistic, so in principle it is possible to achieve an excitonic Bose-Einstein condensate. Time resolved photoluminescence measurements were performed over an extensive range of lattice temperatures and carrier concentrations, in order to determine the fraction of excitons formed from the electron-hole plasma in a quantum well, after non-resonant excitation. The experimental spectra were compared to a pure plasma calculation first, then excitons were taken into account. The highest fraction of formed excitons is found for low temperatures and intermediate carrier densities. This fraction is found to be very small, and this has clear implications on the excitonic Bose-Einstein condensation studies.The photoluminescence emitted left and right from a quantum well is interfered in a modified Mach-Zender interferometer. It is shown that the light emitted on the two paths will interfere for a V-shape geometry and will not for any other paths.A structure formed by placing a quantum well in a field antinode of a resonant planar microcavity exhibits normal mode coupling: splitting of the resonance spectral line. The coherence properties of the photoluminescence from a normal-mode-coupling microcavity are studied using another version of the Mach-Zender interferometer. The degree of coherence measured in this way depends greatly on the pump wavelength and intensity, ranging from zero to 0.8. However, direct observation of the emission speckle shows significant coherence in all cases. The difference is explained by the different methods used to evaluate the coherence.The strong coupling between a quantum dot and a photonic crystal nanocavity is investigated by observation of photoluminescence. A new method of tunning the cavity wavelength by deposition of a thin film of solid Xenon on all the surfaces of the sample is presented. The method allows the scanning of the cavity wavelength with about 5 nm without a decrease in the quality factor and without changing the temperature.Finally, an extensive study of the quality factors of quantum dot photonic crystal nanocavities is presented. The role of the quantum dot ensemble absorption is investigated. At higher excitation levels, lasing is observed and discussed.
Radiation is almost completely reflected within the exciton-polariton stop band of a semiconductor, as in the typical case of CuCl. We predict, however, that a coherently driven exciton-biexciton transition allows for the propagation of a probe light beam within the stop band. The phenomenon is reminiscent of electromagnetically induced transparency effects occurring in three-level atomic systems, except that it here involves delocalized electronic excitations in a crystalline structure via a frequency and wave-vector selective polaritonic mechanism. A well-developed transparency, favored by the narrow linewidth of the biexciton, is established within the stop band where a probe pulse may propagate with significant delays. The transparency window can be controlled via the pump beam detuning and intensity.
We examine the resonance fluorescence from localized excitons in GaAs/AlGaAs quantum wells with increasing excitation power and for different temperatures. Extending our experimental setup by a microscope objective with high numerical aperture in the cryostat, the detection of the emission from localized excitons is possible. We find a nonlinear behaviour of the emitted intensity with increasing laser power, which is explained as a transition of the emission from excitonic to electron-hole plasma states due to many-body effects between excited carriers. This is supported by our theoretical description based on the semiconductor Bloch equations.
A coherently driven exciton–biexciton transition in CuCl enables one to propagate a probe light beam within the exciton-polariton stop-band where radiation is otherwise completely reflected. The stop-band transparency window can be controlled via the pump beam frequency and intensity. The phenomenon is reminiscent of quantum coherence effects occurring in three-level atomic systems, except that it here involves delocalized electronic excitations in a crystal via a frequency and wave-vector selective polaritonic mechanism. Both a free standing slab and a microcavity configuration are theoretically studied. (© 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)