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Commercial InGaN/GaN light emitting diode heterostructures continue to suffer from efficiency droop at high current densities. Droop mitigation strategies target Auger recombination and typically require structural and/or compositional…

We study experimentally and theoretically polarization-dependent luminescence from an ensemble of quantum-dot-like nanostructures with a very large in-plane shape anisotropy (quantum dashes). We show that the measured degree of linear…

Mesoscale and Nanoscale Physics · Physics 2012-01-20 A. Musiał , P. Kaczmarkiewicz , G. Sęk , P. Podemski , P. Machnikowski , J. Misiewicz , S. Hein , S. Höfling , A. Forchel

The GaAs/AlGaAs materials system is well suited to multi-bandgap applications such as the multiple quantum well solar cell. GaAs quantum wells are inserted in the undoped AlGaAs active region of a pin structure to extend the absorption…

Mesoscale and Nanoscale Physics · Physics 2016-06-14 J. P. Connolly , K. W. J. Barnham , J. Nelson , P. Griffin , G. Haarpaintner , C. Roberts , M. Pate , J. S. Roberts

Ultralong trapping of light has been observed in an optically dense three-level solid medium interacting with a pair of counterpropagating coupling fields. Unlike the light trapping based on standing-wave gratings excited by the same…

Quantum Physics · Physics 2009-01-09 B. S. Ham , J. Hahn

The smaller the size of a light-emitting microcavity, the more important it becomes to understand the effects of the cavity boundary on the optical mode profile. Conventional methods of laser physics, such as the paraxial approximation,…

Optics · Physics 2015-06-26 Jens U. Nockel

During the last decade, the laser trapping technique has been actively applied to elucidate the property of macromolecules, DNA, RNA, cytoskeleton fibres, etc. Due to the inherent difficulty in the direct trapping of single molecules at…

Soft Condensed Matter · Physics 2016-08-31 Masatoshi Ichikawa , Kenichi Yoshikawa , Yukiko Matsuzawa

We present detailed discussions of cooling and trapping mechanisms for an atom in an optical trap inside an optical cavity, as relevant to recent experiments. The interference pattern of cavity QED and trapping fields in space makes the…

Quantum Physics · Physics 2009-11-06 S. J. van Enk , J. McKeever , H. J. Kimble , J. Ye

We carry out microphotoluminescence measurements of an acceptor-bound exciton (A^0X) recombination in the applied magnetic field with a single impurity resolution. In order to describe the obtained spectra we develop a theoretical model…

Mesoscale and Nanoscale Physics · Physics 2016-09-16 P. V. Petrov , I. A. Kokurin , G. V. Klimko , S. V. Ivanov , Yu. L. Ivánov , P. M. Koenraad , A. Yu. Silov , N. S. Averkiev

We report on lasing in rolled-up microtube resonators. Time-resolved studies on these semiconductor lasers containing GaAs quantum wells as optical gain material reveal particularly fast turn-on-times and short pulse emissions above the…

Other Condensed Matter · Physics 2015-05-14 Ch. Strelow , M. Sauer , S. Fehringer , T. Korn , C. Schüller , A. Stemmann , Ch. Heyn , D. Heitmann , T. Kipp

Control over spontaneous emission rate is important for improving efficiency in different semiconductor applications including lasers, LEDs and photovoltaics. Usually, an emitter should be placed inside the cavity to increase spontaneous…

We theoretically study the optical properties and the electronic structure of highly elongated quantum dots (quantum dashes) and show how carrier trapping due to geometrical fluctuations of the confining potential affects the excitonic…

Mesoscale and Nanoscale Physics · Physics 2015-06-04 Piotr Kaczmarkiewicz , Paweł Machnikowski

With the aim of improving solar cell efficiency, a structure for realizing electron tunneling from In0.6Al0.4As quantum dots (QDs) through an Al0.4Ga0.6As barrier to AlAs has been grown using molecular beam epitaxy. The photoluminescence…

Mesoscale and Nanoscale Physics · Physics 2013-03-25 Masataka Koyama , Dai Suzuki , Xiangmeng Lu , Yoshiaki Nakata , Shunichi Muto

We propose a cavity based laser cooling and trapping scheme, providing tight confinement and cooling to very low temperatures, without degradation at high particle densities. A bidirectionally pumped ring cavity builds up a resonantly…

Quantum Physics · Physics 2009-11-10 Th. Elsaesser , B. Nagorny , A. Hemmerich

The interaction between molecules and surface plasmons in defined geometries can lead to new light mater hybrid states where light propagation is strongly influenced by molecular photon absorption. Their application range from lasing LEDs…

We study the mechanical effects of light on an atom trapped in a harmonic potential when an atomic dipole transition is driven by a laser and it is strongly coupled to a mode of an optical resonator. We investigate the cooling dynamics in…

Quantum Physics · Physics 2007-09-05 Stefano Zippilli , Giovanna Morigi , Wolfgang P. Schleich

We report on recent experiments investigating the modification of the inter-band optical response of a piezoelectric semiconductor quantum well structure under the influence of intense short period surface acoustic waves. Experimentally, we…

Condensed Matter · Physics 2008-02-03 C. Rocke , A. Wixforth , J. P. Kotthaus , H. Boehm , G. Weimann

Light emitters based on the semiconductor alloy aluminium gallium nitride ((Al,Ga)N) have gained significant attention in recent years due to their potential for a wide range of applications in the ultraviolet (UV) spectral window. However,…

Mesoscale and Nanoscale Physics · Physics 2023-01-11 Robert Finn , Stefan Schulz

Hybrid structures combining ferromagnetic (FM) and semiconductor constituents have great potential for future applications in the field of spintronics. A systematic approach to study spin-dependent transport in the GaMnAs/GaAs/InGaAs…

We report on a dynamic photoconductive gain effect in quantum wires which are lithographically fabricated in an AlGaAs/GaAs quantum well via a shallow-etch technique. The effect allows resolving the one-dimensional subbands of the quantum…

Mesoscale and Nanoscale Physics · Physics 2009-11-13 K. -D. Hof , C. Rossler , S. Manus , J. P. Kotthaus , A. W. Holleitner , D. Schuh , W. Wegscheider

We characterized optically In0.37Ga0.63As/GaAs quantum dots and Al0.2Ga0.8As/Al0.9Ga0.1As distributed Bragg reflector based cavities. The main mechanisms of quantum dots photoluminescence quenching were identified. We measured reflectivity…