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.
The authors report on design, fabrication, and electro‐optical characterization of single‐frequency diode lasers emitting around 696, 707, and 712 nm. This has been achieved by a variation of the ...periods of the 10th order surface Bragg gratings implemented on a single epitaxial wafer. Depending on the wavelength, the devices achieved an optical output power of up to 60 mW at a current of 150 mA and spectral linewidths of about 400 kHz (full width at half maximum (FWHM)) and 20 kHz (Lorentzian).
The influence of the front facet reflectivity on the spectral linewidth of high power DFB (distributed feedback) diode lasers emitting at 780 nm has been investigated theoretically and ...experimentally. Characterization of lasers at various front facet reflections showed substantial reduction of the linewidth. This behavior is in reasonable agreement with simulation results. A minimum linewidth of 8 kHz was achieved at an output power of 85 mW with the laser featuring a front facet reflectivity of 30%. The device with a front facet reflectivity of 5% reached the same linewidth value at an output power of 290 mW.
We present a micro-integrated, extended cavity diode laser module for space-based experiments on potassium Bose-Einstein condensates and atom interferometry. The module emits at the wavelength of the ...potassium D2-line at 766.7 nm and provides 27.5 GHz of continuous tunability. It features sub-100 kHz short term (100 μs) emission linewidth. To qualify the extended cavity diode laser module for quantum optics experiments in space, vibration tests (8.1 g(RMS) and 21.4 g(RMS)) and mechanical shock tests (1500 g) were carried out. No degradation of the electro-optical performance was observed.
Distributed Bragg Reflector semiconductor lasers are ideally suited for quantum technology applications due to their high efficiency, small footprint, and tunability in combination with the frequency ...stability provided by an integrated frequency selective element. Here we present the design, fabrication, and electro-optical characterization of DBR lasers optimized for strontium-based quantum technology applications at 689.449 nm. The devices achieved an optical output power of up to 88 mW, four times more than previously reported, as well as a spectral linewidth of 0.4 MHz.
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.
Bereits Galilei untersuchte, ob verschiedene frei fallende Körper im Schwerefeld der Erde gleich stark beschleunigt werden, die sogenannte Universalität des freien Falls. Die Genauigkeit der ...experimentellen Überprüfungen konnte seitdem beständig gesteigert werden. Einen neuen Ansatz, die Messgenauigkeit noch weiter zu verbessern, bilden quantenmechanische Messmethoden, die auf Materiewelleninterferometrie beruhen. Die dabei genutzten Apparaturen verwenden Laserstrahlung zur Kühlung, Manipulation und Detektion der Atome. Ziel der vorliegenden Arbeit war die Entwicklung des Lasersystems für ein neues Experiment, das erstmals Zwei-Spezies-Atominterferometrie (mit Rb & K) in Mikrogravitation demonstrieren soll.;
Ein Lasersystem, das sowohl die funktionalen Anforderungen als auch die aus dem Einsatz auf dem Katapult des Fallturms resultierenden Anforderung (Volumen < 44 l, Masse < 35 kg und voll funktionsfähig sofort nach einem Katapultstart mit Beschleunigungen von 30 g) erfüllt, wurde funktional konzipiert und mechanisch designt. Zur Demonstration wurde der Rubidium-Teil des Lasersystems funktional sowie mechanisch qualifiziert. Inzwischen wird er routinemäßig für Experimente am Fallturm eingesetzt.;
Für das Lasersystem wurden kompakte und robuste schmalbandigen Lasermodule entwickelt. Diese liefern bei einer Grundfläche der optischen Bank von nur 10 mm x 50 mm Ausgangsleistungen von bis zu 3,7 W. Am Arbeitspunkt (1 W Ausgangsleistung) besitzen die Strahlquellen Linienbreiten im Bereich von 100 kHz (Lorentz) bzw. 1 MHz (-3 dB, 10 µs). ;
Zum Nachweis der spektralen Stabilität der Lasermodule wurde ein Messverfahrens zur Charakterisierung des Frequenzrauschens freilaufender Laser entwickelt. Dieses basiert auf einer Schwebungsmessung mit anschließender Analyse der Quadraturkomponenten des Signals im Zeitbereich. Durch den Einsatz geeigneter Filter erlaubt es die Unterdrückung der für Diodenlaser typischen Frequenzdrifts.
Galileo, already, investigated whether different free falling bodies in the gravitational field of the Earth are accelerated at the same rate, the so-called universality of the free fall. The accuracy of the experimental tests has been steadily increased ever since. A new approach to further increase the measurement accuracy is provided by quantum mechanical measurements based on matter wave interferometry. The apparatuses used for this purpose employ laser radiation for cooling, manipulation, and detection of the atoms. The aim of this thesis’ work was the development of the laser system for a new experiment intended to demonstrate two-species atom interferometry (utilizing Rb & K) in microgravity for the first time.;
A laser system, which fulfills the functional requirements as well as the requirements resulting from the deployment on the catapult of the drop tower (volume < 44 l, mass < 35 kg, and fully functional immediately after a catapult launch with accelerations of 30 g), has been functionally conceived and mechanically designed. For demonstration, the rubidium part of the laser system was functionally and mechanically qualified. By now, it is routinely used for experiments at the drop tower.;
For the laser system, compact and robust spectrally narrow laser modules have been developed. These provide an output power up to 3.7 W at a footprint of the optical bench of only 10 mm × 50 mm. At the operating point (1 W output power), the radiation sources exhibit linewidths in the range of 100 kHz (Lorentzian) and 1 MHz (−3 dB, 10 μs).;
To validate the spectral stability of the laser modules a measuring method for the characterization of the frequency noise of free-running lasers has been developed. This method is based on a beat note measurement with subsequent analysis of the quadrature components of the signal in the time domain. By utilizing appropriate filters, it allows for the suppression of the frequency drifts that are typical for diode lasers.
We report on the realization of narrow linewidth high power DFB diode lasers emitting near 1064 nm in stable longitudinal and lateral single mode. The linewidth is analyzed in dependence of the ...output power for lasers with cavity lengths of 1 and 2 mm by means of a heterodyne beat note technique. The minimum intrinsic linewidth is 22 kHz FWHM (full width at half maximum, at 100 μ s time scale) for an output power of 150 mW and a cavity length of 2 mm. The minimum total linewidth is mainly determined by technical noise and corresponds to 234 kHz FWHM at an output power of 70 mW. The influence of current noise on the linewidth is investigated and compared for different cavity lengths. Re-broadening at high output power is only observed for the contribution of technical noise to the linewidth. The intrinsic linewidth shows the theoretically expected 1/P out -dependence at all power levels.
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