Broad spectrum measurement of the birefringence of an isothiocyanate based liquid crystal.

Tunable materials with high anisotropy of refractive index and low loss are of particular interest in the microwave and terahertz range. Nematic liquid crystals are highly sensitive to electric and magnetic fields and may be designed to have particularly high birefringence. In this paper we investigate birefringence and absorption losses in an isothiocyanate based liquid crystal (designed for high anisotropy) in a broad range of the electromagnetic spectrum, namely 0.1-4 GHz, 30 GHz, 0.5-1.8 THz, and in the visible and near-infrared region (400 nm-1600 nm). We report high birefringence (Δn = 0.19-0.395) and low loss in this material. This is attractive for tunable microwave and terahertz device applications

Surface-emitting photonic crystal terahertz quantum cascade lasers

Surface-emitting terahertz quantum cascade lasers based on double-metal waveguides incorporating photonic crystal structures have been demonstrated. Far-field emission patterns are dominated by lobes close to the surface normal. In addition to modified emission profiles, enhanced output powers are also displayed in comparison to standard ridge waveguides, with over 2 mW peak power observed at a heat sink temperature of 10 K

Controlling the ultrafast dynamics of THz quantum cascade lasers using gain switching

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In Situ Generation of Surface Plasmon Polaritons Using a Near-Infrared Laser Diode

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Terahertz radiation from magnetic excitations in diluted magnetic semiconductors

We probed, in the time domain, the THz electromagnetic radiation originating from spins in CdMnTe diluted magnetic semiconductor quantum wells containing high-mobility electron gas. Taking advantage of the efficient Raman generation process, the spin precession was induced by low power near-infrared pulses. We provide a full theoretical first-principles description of spin-wave generation, spin precession, and of emission of THz radiation. Our results open new perspectives for improved control of the direct coupling between spin and an electromagnetic field, e.g., by using semiconductor technology to insert the THz sources in cavities or pillars.Fil: Rungsawang, R.. Ecole Normale Supérieure; Francia. Universite Pierre et Marie Curie; Francia. Centre National de la Recherche Scientifique; FranciaFil: Perez, F.. Universite de Paris VI. Institut des Nanosciences de Paris; FranciaFil: Oustinov, D.. Ecole Normale Supérieure; Francia. Universite Pierre et Marie Curie; Francia. Centre National de la Recherche Scientifique; FranciaFil: Gomez, Javier Enrique. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte; Argentina. Universite de Paris VI. Institut des Nanosciences de Paris; . Comisión Nacional de Energía Atómica. Centro Atómico Bariloche; ArgentinaFil: Kolkovsky, V.. Polish Academy of Sciences; PoloniaFil: Karczewski, G.. Polish Academy of Sciences; PoloniaFil: Wojtowicz, T.. Polish Academy of Sciences; PoloniaFil: Madéo, J.. Ecole Normale Supérieure; Francia. Universite Pierre et Marie Curie; Francia. Centre National de la Recherche Scientifique; FranciaFil: Jukam, N.. Centre National de la Recherche Scientifique; Francia. Ecole Normale Supérieure; Francia. Universite Pierre et Marie Curie;Fil: Dhillon, S.. Centre National de la Recherche Scientifique; Francia. Ecole Normale Supérieure; Francia. Universite Pierre et Marie Curie;Fil: Tignon, J.. Centre National de la Recherche Scientifique; Francia. Ecole Normale Supérieure; Francia. Universite Pierre et Marie Curie