Waqas W. Ahmed

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W. W. Ahmed, S. Kumar, R. Herrero, M. Botey, M. Radziunas and K. Staliunas Departament de Fisica i Enginyeria Nuclear, Universitat Politècnica de Catalunya (UPC), Colom 11, E-08222 Terrassa, Barcelona, Spain Weierstrass Institute for Applied Analysis and Stochastics, Leibniz Institute in Forschungsverbund Berlin e.V., Mohrenstrasse 39, 10117 Berlin, Germany(More)
Semiconductor Lasers and particularly Vertical-Cavity Surface-Emitting Lasers (VCSELs) are important laser sources used for many purposes. However, the applications of these lasers are mainly restricted by their strongly multimode operation given by the lack of an intrinsic transverse mode selection mechanism [1]. The introduction of an axial PT-symmetric(More)
Semiconductor lasers are efficient light sources with an important drawback, the lack of an intrinsic mode selection mechanism which leads to spatio-temporal instabilities. The modulation instability that unstabilizes the homogeneous solution can be suppressed by the introduction of spatial modulations in the transverse and longitudinal directions. The(More)
Optical Parity-Time (PT-) symmetric systems support unusual properties. When the symmetric coupling between internal modes is broken the system becomes strongly unidirectional resulting in novel effects such as asymmetric reflections, invisibility or asymmetric mode coupling. Here, we propose a new class of nanophotonic PT-axisymmetric systems which lead to(More)
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