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Saint Petersburg, Russia

Kavokin K.V.,RAS Ioffe Physical - Technical Institute | Kaliteevski M.A.,Durham University | Abram R.A.,Durham University | Kavokin A.V.,University of Southampton | And 3 more authors.
Applied Physics Letters | Year: 2010

We show that planar semiconductor microcavities in the strong coupling regime can be used as sources of stimulated terahertz radiation. Emitted terahertz photons would have a frequency equal to the splitting of the cavity polariton modes. The optical transition between upper and lower polariton branches is allowed due to mixing of the upper polariton state with one of the excited exciton states and is stimulated in the polariton laser regime. © 2010 American Institute of Physics. Source

Sokolovskii G.S.,RAS Ioffe Physical - Technical Institute | Viktorov E.A.,National Research University of Information Technologies | Viktorov E.A.,Vrije Universiteit Brussel | Abusaa M.,Vrije Universiteit Brussel | And 14 more authors.
Applied Physics Letters | Year: 2015

We examine the response of a pulse pumped quantum dot laser both experimentally and numerically. As the maximum of the pump pulse comes closer to the excited-state threshold, the output pulse shape becomes unstable and leads to dropouts. We conjecture that these instabilities result from an increase of the linewidth enhancement factor α as the pump parameter comes close to the excitated state threshold. In order to analyze the dynamical mechanism of the dropout, we consider two cases for which the laser exhibits either a jump to a different single mode or a jump to fast intensity oscillations. The origin of these two instabilities is clarified by a combined analytical and numerical bifurcation diagram of the steady state intensity modes. © 2015 AIP Publishing LLC. Source

Savenko I.G.,University of Iceland | Savenko I.G.,Academic University | Shelykh I.A.,University of Iceland | Shelykh I.A.,International Institute of Physics | Kaliteevski M.A.,RAS Ioffe Physical - Technical Institute
Physical Review Letters | Year: 2011

We consider the nonlinear terahertz emission by the system of cavity polaritons in the regime of polariton lasing. To account for the quantum nature of terahertz-polariton coupling, we use the Lindblad master equation approach and demonstrate that quantum microcavities reveal a rich variety of nonlinear phenomena in the terahertz range, including bistability, short terahertz pulse generation, and terahertz switching. © 2011 American Physical Society. Source

Huletski A.,Academic University | Kartashov D.,Academic University | Krinkin K.,Saint Petersburg State University
Conference of Open Innovation Association, FRUCT | Year: 2015

Nowadays the big challenge in simultaneous localization and mapping (SLAM) of mobile robots is the creation of efficient and robust algorithms. Big amount of SLAM methods use computer vision for extraction of unique environment features from camera images (feature-based approach). In some cases, artificial landmarks are being used to simplify environment markup (landmark-based approach). In this paper we introduce a new QR-like color artificial landmark design and algorithm for fast detecting and tracking them in arbitrary images. © 2015 FRUCT Oy. Source

Nikolenko S.I.,Academic University | Korobeynikov A.I.,Saint Petersburg State University | Alekseyev M.A.,University of South Carolina
BMC Genomics | Year: 2013

Error correction of sequenced reads remains a difficult task, especially in single-cell sequencing projects with extremely non-uniform coverage. While existing error correction tools designed for standard (multi-cell) sequencing data usually come up short in single-cell sequencing projects, algorithms actually used for single-cell error correction have been so far very simplistic. We introduce several novel algorithms based on Hamming graphs and Bayesian subclustering in our new error correction tool BAYESHAMMER. While BAYESHAMMER was designed for single-cell sequencing, we demonstrate that it also improves on existing error correction tools for multi-cell sequencing data while working much faster on real-life datasets. We benchmark BAYESHAMMER on both k-mer counts and actual assembly results with the SPADES genome assembler. © 2013 Nikolenko et al. Source

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