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Long-range and fast transport of coherent excitons is important for development of high-speed excitonic circuits and quantum computing applications. However, most of these coherent excitons have only been observed in some low-dimensional…

Colloidal 2D semiconductor nanoplatelets are highly efficient light emitters, which exhibit large absorption and emission cross sections, and constitute promising laser gain media. However, if dispersed in solutions, such nanoplatelets lack…

Excitons in semiconductors may form correlated phases at low temperatures. We report the observation of an exciton liquid in GaAs/AlGaAs coupled quantum wells. Above a critical density and below a critical temperature the photogenerated…

Mesoscale and Nanoscale Physics · Physics 2015-03-13 Michael Stern , Vladimir Umansky , Israel Bar-Joseph

A new mechanism for exciton lasing in ZnSe/ZnCdSe quantum wells is proposed. Lasing, occurring below the lowest exciton line, may be associated with a BCS-like condensed (coherent) exciton state. This state is most stable at low…

Condensed Matter · Physics 2009-10-28 M. E. Flatte' , E. Runge , H. Ehrenreich

We demonstrate the possibility of the optical orientation of excitons in the near field of the metal grating that covers a semiconductor nanostructure. Excitons generated this way have the wave vector greater than the wave vector of the…

Mesoscale and Nanoscale Physics · Physics 2024-03-21 A. V. Korotchenkov , N. S. Averkiev

Multiple exciton generation is a process in which more than one electron hole pair is generated per absorbed photon. It allows us to increase the efficiency of solar energy harvesting. Experimental studies have shown the multiple exciton…

Mesoscale and Nanoscale Physics · Physics 2016-08-11 Fikeraddis A. Damtie , Khadga J. Karki , Tõnu Pullerits , Andreas Wacker

Strongly quantum-confined 2D colloidal PbS nanoplatelets (NPLs) are highly interesting materials for near-infrared optoelectronic applications. Here, we use ultrafast transient optical absorption spectroscopy to study the characteristics…

Previous single-particle spectroscopic studies of colloidal quantum dots have indicated a significant spread in biexciton lifetimes across an ensemble of nominally identical nanocrystals. It has been speculated that in addition to…

Materials Science · Physics 2013-09-24 Young-Shin Park , Wan Ki Bae , Lazaro A. Padilha , Jeffrey M. Pietryga , Victor I. Klimov

The quasiparticle band structure and optical properties of single-walled zigzag and armchair SiC nanotubes (SiC-NTs) as well as single SiC sheet are investigated by ab initio many-body calculations using the GW and the GW plus…

Mesoscale and Nanoscale Physics · Physics 2011-08-23 H. C. Hsueh , G. Y. Guo , Steven G. Louie

Accurate and efficient calculation of optical response properties of solid materials is still challenging. We present a meta-generalized gradient approximation (metaGGA) density functional based time-dependent and dielectric function…

Materials Science · Physics 2024-09-10 Hong Tang , Niraj Pangeni , Adrienn Ruzsinszky

Electron transfer to an individual quantum dot promotes the formation of charged excitons with enhanced recombination pathways and reduced lifetimes. Excitons with only one or two extra charges have been observed and exploited for very…

A design strategy for achieving broadband optical gain in GaSb-based semiconductor amplifiers operating beyond 2 \mu m is presented. By employing asymmetric GaInSb/AlGaAsSb quantum wells (QWs) of varying thicknesses, a flat and wide gain…

The strong Coulomb interactions and the small exciton radii in two-dimensional metal dichalcogenides can result in very fast capture of electrons and holes of excitons by mid-gap defects from Auger processes. In the Auger processes…

Mesoscale and Nanoscale Physics · Physics 2015-04-22 Haining Wang , Jared H. Strait , Changjian Zhang , Weimin Chan , Christina Manolatou , Sandip Tiwari , Farhan Rana

Optical properties of single-wall carbon nanotubes (SWCNTs) for light polarized parallel to the nanotube axis have been extensively studied, whereas their response to light polarized perpendicular to the nanotube axis has not been well…

Mesoscale and Nanoscale Physics · Physics 2019-01-23 Fumiya Katsutani , Weilu Gao , Xinwei Li , Yota Ichinose , Yohei Yomogida , Kazuhiro Yanagi , Junichiro Kono

Two dimensional (2D) semiconductors present unique opportunities to intertwine optical and magnetic functionalities and to tune these performances through defects and dopants. Here, we integrate exciton pumping into a quantum sensing…

Previously, we had proposed an optically-pumped five-level Gain EIT (GEIT) system, which has a transparency dip superimposed on a gain profile and exhibits a negative dispersion suitable for the white-light-cavity signal-recycling (WLC-SR)…

Instrumentation and Detectors · Physics 2017-08-23 Minchuan Zhou , Zifan Zhou , Selim M. Shahriar

Multiexcitonic transitions and emission of several photons per excitation comprise a very attractive feature of semiconductor quantum dots for optoelectronics applications. However, these higher-order radiative processes are usually…

From a systematic study of the threshold current density as a function of temperature and hydrostatic pressure, in conjunction with theoretical analysis of the gain and threshold carrier density, we have determined the wavelength dependence…

Coherence transfer is a multi-disciplinary topic of interest, including chemistry, biology and physics. In quantum technologies, achieving non-local coherent coupling between solid-state qubits is of the utmost importance. Here, we…

In quantum dots (QDs) the Auger recombination is a non-radiative process, where the electron-hole recombination energy is transferred to an additional carrier. It has been studied mostly in colloidal QDs, where the Auger recombination time…

Mesoscale and Nanoscale Physics · Physics 2019-07-03 Annika Kurzmann , Arne Ludwig , Andreas D. Wieck , Axel Lorke , Martin Geller