Local Strain Effects in Near-Field Spectra of Single Semiconductor Quantum Dots.

2002 ◽  
Vol 737 ◽  
Author(s):  
A. M. Mintairov ◽  
P. A. Blagnov ◽  
O. V. Kovalenkov ◽  
C. Li ◽  
J. L. Merz ◽  
...  
Keyword(s):  
Ground State ◽  
Near Field ◽  
Local Strain ◽  
Energy Shift ◽  
High Energy ◽  
Emission Lines ◽  
Strain Component ◽  
Aperture Diameter ◽  
Pressure Coefficients ◽  
Theoretical Investigations

ABSTRACTExperimental and theoretical investigations of high-energy shifts of single InAs, InGaAs, InAlAs and InP quantum dot (QD) emission lines induced by contact pressure exerted by a near-field optical fiber tip are reported. “Pressure” coefficients of 0.65–3.5 meV/nm have been measured for ground state emission lines in agreement with numerical calculations. We show that the observed increase of the tip-induced energy shift with increasing aperture diameter is caused by a decrease of the uniaxial strain component. We also report the effect of emission instability of single QD emission intensity under tip-induced pressure.

Mechanical Interaction in Near-Field Spectroscopy of single Semiconductor Quantum Dots.

2002 ◽  
Vol 722 ◽  
Author(s):  
A. M. Mintairov ◽  
P. A. Blagnov ◽  
O. V. Kovalenkov ◽  
C. Li ◽  
J. L. Merz ◽  
...  
Keyword(s):  
Near Field ◽  
Local Strain ◽  
High Energy ◽  
Emission Lines ◽  
Mechanical Interaction ◽  
Aperture Diameter ◽  
Self Organized ◽  
Order Of Magnitude ◽  
Single Quantum Dot ◽  
Magnitude Increase

AbstractWe have studied high-energy shifts of single quantum dot (QD) emission lines induced by contact pressure exerted by a near-field optical fiber tip. “Pressure” coefficients of 0.65-3 meV/nm have been measured for self-organized InAs/GaAs, InAs/AlAs and InP/GaInP QDs in agreement with numerical calculations of the local strain field. We found an increase of the tipinduced pressure with increasing aperture diameter from 50-300 nm. A correlation between the shift rate and QD stiffness was obtained. We also observed an order of magnitude increase of single QD emission intensity with increased pressure.

scholarly journals Splicing technology of Ti:sapphire crystals for a high-energy chirped pulse amplifier laser system

2014 ◽  
Vol 2 ◽  
Author(s):  
Yanqi Liu ◽  
Yuxin Leng ◽  
Xiaoming Lu ◽  
Yi Xu ◽  
Cheng Wang
Keyword(s):  
Near Field ◽  
Laser System ◽  
Output Pulse ◽  
High Energy ◽  
Amplification Efficiency ◽  
Chirped Pulse ◽  
Temporal Profile ◽  
Large Size ◽  
Theoretical Investigations ◽  
Pulse Amplifier

AbstractWe develop a splicing technology of Ti:sapphire crystals for a high-energy chirped pulse amplifier laser system that can suppress the parasitic lasing to improve the amplification efficiency compared to a large-size single Ti:sapphire crystal amplifier. Theoretical investigations on the characteristics of the amplifier with four splicing Ti:sapphire crystals, such as parasitic-lasing suppression and amplification efficiencies, are carried out. Some possible issues resulting from this splicing technology, including spectral modulation, stretching or splitting of the temporal profile, and the sidelobe generation in the spatial domain (near field and far field), are also investigated. Moreover, the feasibility of the splicing technology is preliminarily demonstrated in an experiment with a small splicing Ti:sapphire crystals amplifier. The temporal profile and spatial distribution of the output pulse from the splicing Ti:sapphire crystal amplifier are discussed in relation to the output pulse from a single Ti:sapphire crystal amplifier.

Narrow high-energy emission lines in high-resolution near-field spectroscopy on GaInN/GaN quantum wells

2004 ◽  
Vol 1 (10) ◽  
pp. 2520-2523 ◽  
Author(s):  
F. Hitzel ◽  
G. Klewer ◽  
S. Lahmann ◽  
U. Rossow ◽  
A. Hangleiter
Keyword(s):  
High Resolution ◽  
Quantum Wells ◽  
Near Field ◽  
High Energy ◽  
Emission Lines ◽  
Energy Emission ◽  
Field Spectroscopy ◽  
High Energy Emission

Near-Field Magneto-Photoluminescence of Singe Self-Organized Quantum Dots.

2003 ◽  
Vol 794 ◽  
Author(s):  
A. M. Mintairov ◽  
A. S. Vlasov ◽  
J. L. Merz
Keyword(s):  
Quantum Dots ◽  
Near Field ◽  
Energy Shift ◽  
Zeeman Splitting ◽  
Negative Energy ◽  
Zero Magnetic Field ◽  
Bimodal Size Distribution ◽  
Self Organized ◽  
Scanning Optical Microscopy ◽  
Near Field Scanning

ABSTRACTWe present results obtained using low temperature near-field scanning optical microscopy for the measurements of Zeeman splitting and the diamagnetic shift of single self-organized InAs/AlAs, InAs/GaAs and InP/GaInP quantum dots. The measurements allow us to relate the bimodal size distribution of InAs dots with variations in In content. For single InP QDs we observed a strong circular polarization at zero magnetic field accompanied with a negative energy shift, suggesting that strong internal magnetic fields exist in these QDs.

Lateral Coupling of Self-Assembled Quantum Dots Studied by Near-Field Spectroscopy

1999 ◽  
Vol 571 ◽  
Author(s):  
H.D. Robinson ◽  
B.B. Goldberg ◽  
J.L. Merz
Keyword(s):  
Quantum Dots ◽  
Additional Data ◽  
High Spatial Resolution ◽  
Large Fraction ◽  
Near Field ◽  
Localized States ◽  
Emission Lines ◽  
Lateral Coupling ◽  
Self Assembled ◽  
Density Regime

ABSTRACTLateral coupling between separate quantum dots has been observed in a system of In0.55A10.45As self-assembled quantum dots. The experiment was performed by taking photoluminescence excitation (PLE) spectra in the optical near-field at 4.2 K. The high spatial resolution afforded by the near-field technique allows us to resolve individual dots in a density regime where interactions between neighboring dots become apparent. In the PLE spectra, narrow resonances are observed in the emission lines of individual dots. A large fraction of these resonances occur simultaneously in several emission lines, originating from different quantum dots. This is evidence of interdot scattering of carriers, which additional data show to be mediated by localized states at energies below the wetting layer exciton energy. A very rich phonon spectrum generated by the complicated interfaces between barrier and dot material is also evident in the data.

scholarly journals Exciton-polaron Rydberg states in monolayer MoSe2 and WSe2

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Erfu Liu ◽  
Jeremiah van Baren ◽  
Zhengguang Lu ◽  
Takashi Taniguchi ◽  
Kenji Watanabe ◽  
...  
Keyword(s):  
Boron Nitride ◽  
Excited States ◽  
Ground State ◽  
Transition Metal Dichalcogenides ◽  
Rydberg States ◽  
Energy Shift ◽  
Many Body ◽  
Electron Hole ◽  
Metal Dichalcogenides ◽  
Excitonic States

AbstractExciton polaron is a hypothetical many-body quasiparticle that involves an exciton dressed with a polarized electron-hole cloud in the Fermi sea. It has been evoked to explain the excitonic spectra of charged monolayer transition metal dichalcogenides, but the studies were limited to the ground state. Here we measure the reflection and photoluminescence of monolayer MoSe2 and WSe2 gating devices encapsulated by boron nitride. We observe gate-tunable exciton polarons associated with the 1 s–3 s exciton Rydberg states. The ground and excited exciton polarons exhibit comparable energy redshift (15~30 meV) from their respective bare excitons. The robust excited states contradict the trion picture because the trions are expected to dissociate in the excited states. When the Fermi sea expands, we observe increasingly severe suppression and steep energy shift from low to high exciton-polaron Rydberg states. Their gate-dependent energy shifts go beyond the trion description but match our exciton-polaron theory. Our experiment and theory demonstrate the exciton-polaron nature of both the ground and excited excitonic states in charged monolayer MoSe2 and WSe2.

Si2p Core Level Absorption and Photoemission Spectra of Porous Si

1992 ◽  
Vol 283 ◽  
Author(s):  
Hisao Nakashima ◽  
Koichi Inoue ◽  
Kenzo Maehashi
Keyword(s):  
Synchrotron Radiation ◽  
Electronic Structures ◽  
Energy Shift ◽  
Blue Shift ◽  
Photo Luminescence ◽  
High Energy ◽  
Core Level ◽  
Oxidation States ◽  
Porous Si ◽  
The Core

ABSTRACTSi2p core level absorption and photoemission spectra are taken for different porous Si layers using synchrotron radiation, toknow the electronic structures of porous Si. The core level absorption spectra show the high energy shift of the conduction band which correlates with the photo-luminescence blue shift. The oxidation states of porous Si are clarified from the photoemission spectra.

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