Igor Khanonkin

Bio: Igor Khanonkin is an academic researcher from Technion – Israel Institute of Technology. The author has contributed to research in topics: Quantum dot & Quantum dot laser. The author has an hindex of 3, co-authored 19 publications receiving 45 citations.

Carrier Dynamics in a 1.55 μm Tunneling Injection Quantum Dot Semiconductor Optical Amplifier

Abstract: Carrier dynamics following a short pulse perturbation in a tunneling-injection quantum dot (QD) gain medium are analyzed. A hybrid state comprising the injection-well and QD first excited state dominate the dynamics with a time constant of 1ps. The role of the perturbation wavelength is discussed.

Ultra-fast charge carrier dynamics across the spectrum of an optical gain media based on InAs/AlGaInAs/InP quantum dots

Abstract: The charge carrier dynamics of improved InP-based InAs/AlGaInAs quantum dot (QD) semiconductor optical amplifiers are examined employing the multi-wavelength ultrafast pump-probe measurement technique. The transient transmission response of the continuous wave probe shows interesting dynamical processes during the initial 2-3 ps after the pump pulse, when carriers originating from two photon absorption contribute the least to the recovery. The effects of optical excitations and electrical bias levels on the recovery dynamics of the gain in energetically different QDs are quantified and discussed. The experimental observations are validated qualitatively using a comprehensive finite-difference time-domain model by recording the time evolution of the charge carriers in the QDs ensemble following the pulse.

1.5-mm Indium Phosphide-Based Quantum Dot Lasers and Optical Amplifiers: The Impact of Atom-Like Optical Gain Material for Optoelectronics Devices

Abstract: Using quantum dot (QD) structures as active material for optoelectronics was already in focus before the development of quantum well (QW) lasers and before semiconductor lasers occupied an important place in the market. The big step in reducing laser threshold conditions by substituting bulk gain materials with QWs should find a logical continuation by further reducing the dimensionality toward full 3D carrier confinement by QDs. This was predicted by theoretical considerations at the beginning of the 1980s [1], [2]. However, no practical technologies were available at that time. Top-down approaches, as originally addressed, to produce nanoscale species on very large surfaces and interface areas resulted in the accumulation of a large defect density within the active region and the domination of nonradiative carrier recombination mechanisms. Only during the early 1990s was a major breakthrough achieved with the introduction of the bottom-up approach of strain-driven, self-organized epitaxial QD growth. The first lasers were obtained in the gallium arsenide (GaAs)-based material system [3].

Ramsey fringes in a room-temperature quantum-dot semiconductor optical amplifier

Abstract: Ramsey interference that enables careful control over quantum states is demonstrated here in an inhomogeneously broadened ensemble of quantum dots, which serve as the gain medium of a semiconductor waveguide operating at room temperature. A subfemtosecond-resolution pump-probe scheme reveals a clear oscillatory behavior of the amplitude and instantaneous frequency of the probe pulse. A unique phenomenon is also observed, whereby the temporal position of the output probe pulse also oscillates with the same periodicity. The latter cannot be observed in single-dot systems since it results from the distributed nature of the amplifier.

Generation of Non-classical Motional States of a Trapped Atom

Abstract: We report the creation of thermal, Fock, coherent, and squeezed states of motion of a harmonically bound {sup 9}Be{sup +} ion. The last three states are coherently prepared from an ion which has been initially laser cooled to the zero point of motion. The ion is trapped in the regime where the coupling between its motional and internal states, due to applied (classical) radiation, can be described by a Jaynes-Cummings-type interaction. With this coupling, the evolution of the internal atomic state provides a signature of the number state distribution of the motion. {copyright} {ital 1996 The American Physical Society.}

Photon Enhanced Thermionic Emission for Solar Concentrator Systems

Abstract: Solar-energy conversion usually takes one of two forms: the 'quantum' approach, which uses the large per-photon energy of solar radiation to excite electrons, as in photovoltaic cells, or the 'thermal' approach, which uses concentrated sunlight as a thermal-energy source to indirectly produce electricity using a heat engine. Here we present a new concept for solar electricity generation, photon-enhanced thermionic emission, which combines quantum and thermal mechanisms into a single physical process. The device is based on thermionic emission of photoexcited electrons from a semiconductor cathode at high temperature. Temperature-dependent photoemission-yield measurements from GaN show strong evidence for photon-enhanced thermionic emission, and calculated efficiencies for idealized devices can exceed the theoretical limits of single-junction photovoltaic cells. The proposed solar converter would operate at temperatures exceeding 200 degrees C, enabling its waste heat to be used to power a secondary thermal engine, boosting theoretical combined conversion efficiencies above 50%.

서울 소재 7개 종합병원 암환자들의 보완대체요법 이용양상

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Semiconductor science and technology, and Nobel physics prizes

Abstract: Semiconductor science and technology (S T) is a very active branch in the field of natural science, and is also a typical example embodying the development of advanced S T. The Nobel prize for physics is a prize of the highest honour in the world, and there are certain relationships between this award and semiconductor S T. We explore and analyze these inherent relationships which have practical importance for our understanding of the development of semiconductor S T and for predicting its future.