2023, Tyborski, Christoph, Hassan, Muhammad T., Flisgen, Thomas, Schiemangk, Max, Wicht, Andreas

We determine Faraday rotations and measure the optical reflection and transmission from magneto-optical Cd1−xMnxTe crystals with various stoichiometric ratios. For wavelengths between 675 and 1025 nm, we derive Verdet constants, optical loss coefficients, and the complex indices of reflection that are relevant measures to find suitable stoichiometric ratios of Cd1−xMnxTe for the realization of miniaturized optical isolators. By reflection and transmission measurements, we determine the stoichiometric ratios of several different Cd1−xMnxTe crystals and discuss the observed dependence of the optical properties on the stoichiometric ratio with respect to their use in optical isolators. Finally, we show the relevant figure of merit, i.e., the ratio of Verdet constants and optical loss coefficients for Cd1−xMnxTe crystals with Mn contents ranging from x = 0.14 to x = 0.50.

2021, Lachmann, Maike D., Ahlers, Holger, Becker, Dennis, Dinkelaker, Aline N., Grosse, Jens, Hellmig, Ortwin, Müntinga, Hauke, Schkolnik, Vladimir, Seidel, Stephan T., Wendrich, Thijs, Wenzlawski, André, Carrick, Benjamin, Gaaloul, Naceur, Lüdtke, Daniel, Braxmaier, Claus, Ertmer, Wolfgang, Krutzik, Markus, Lämmerzahl, Claus, Peters, Achim, Schleich, Wolfgang P., Sengstock, Klaus, Wicht, Andreas, Windpassinger, Patrick, Rasel, Ernst M.

Bose-Einstein condensates (BECs) in free fall constitute a promising source for space-borne interferometry. Indeed, BECs enjoy a slowly expanding wave function, display a large spatial coherence and can be engineered and probed by optical techniques. Here we explore matter-wave fringes of multiple spinor components of a BEC released in free fall employing light-pulses to drive Bragg processes and induce phase imprinting on a sounding rocket. The prevailing microgravity played a crucial role in the observation of these interferences which not only reveal the spatial coherence of the condensates but also allow us to measure differential forces. Our work marks the beginning of matter-wave interferometry in space with future applications in fundamental physics, navigation and earth observation.

2014, Radziunas, Mindaugas, Tronciu, Vasile Z., Luvsandamdin, Erdenetsetseg, Kürbis, Christian, Wicht, Andreas, Wenzel, Hans

This paper reports the results of numerical and experimental investigations of the dynamics of an external cavity diode laser device composed of a semiconductor laser and a distant Bragg grating, which provides an optical feedback. Due to the influence of the feedback, this system can operate at different dynamic regimes. The traveling wave model is used for simulations and analysis of the nonlinear dynamics in the considered laser device. Based on this model, a detailed analysis of the optical modes is performed, and the stability of the stationary states is discussed. It is shown, that the results obtained from the simulation and analysis of the device are in good agreement with experimental findings.