Erdenetsetseg Luvsandamdin

Micro-integrated extended cavity diode lasers for precision potassium spectroscopy in space

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.

Miniaturized Lab System for Future Cold Atom Experiments in Microgravity

We present the technical realization of a compact system for performing experiments with cold 87Rb and 39K atoms in microgravity in the future. The whole system fits into a capsule to be used in the drop tower Bremen. One of the advantages of a microgravity environment is long time evolution of atomic clouds which yields higher sensitivities in atom interferometer measurements. We give a full description of the system containing an experimental chamber with ultra-high vacuum conditions, miniaturized laser systems, a high-power thulium-doped fiber laser, the electronics and the power management. In a two-stage magneto-optical trap atoms should be cooled to the low μK regime. The thulium-doped fiber laser will create an optical dipole trap which will allow further cooling to sub- μK temperatures. The presented system fulfills the demanding requirements on size and power management for cold atom experiments on a microgravity platform, especially with respect to the use of an optical dipole trap. A first test in microgravity, including the creation of a cold Rb ensemble, shows the functionality of the system.

Study of Microintegrated External-Cavity Diode Lasers: Simulations, Analysis, and Experiments

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 an external Bragg grating, which provides optical feedback. Due to the influence of the feedback, this system can operate in 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 a good qualitative agreement with the experimental findings.

Compact narrow linewidth diode laser modules for precision quantum optics experiments on board of sounding rockets

We have realized a laser platform based on GaAs diode lasers that allows for an operation in mobile exper-imental setups in harsh environments, such as on sounding rockets. The platform comes in two versions: a master-oscillator-power-amplifier and an extended cavity diode laser. Our very robust micro-optical bench has a footprint of 80 x 25 mm2. It strictly omits any movable parts. Master-oscillator-power-amplifier systems based on distributed feedback master oscillators for 767 nm and 780 nm narrow linewidth emission have been implemented by now. A continuous wave optical output power of > 1 W with a power conversion efficiency of > 25% could be achieved. The continuous tuning range of these lasers is on the order of 100 GHz, the linewidth at 10 μs is about 1 MHz. For applications demanding a narrower linewidth we have developed an extended cavity diode laser that achieves a linewidth of 100 kHz at 10 μs. These lasers achieve a continuous spectral tuning range of about 50 GHz and an continuous wave optical power up to 30 mW. The modules have been successfully vibration tested up to 29 gRMS along all three axes and passed 1500 g shocks, again along all 3 axes. Both, master-oscillator-power-amplifiers and extended cavity diode lasers, have been employed in sounding rocket experiments.

Micro-integrated ECDLs for precision spectroscopy in space

We present a micro-integrated, high power, narrow linewidth extended cavity diode laser (ECDL) for precision quantum optics experiments at 780 nm onboard a sounding rocket. Although micro-integrated ECDL is based on a Littrow configuration, it features an excellent mechanical stability because any moveable parts were omitted. It provides an overall tuneability of 40 GHz and a continuous tuneability of 4 GHz. We have demonstrated a maximum output power of more than 120 mW, an intrinsic linewidth of approximately 3.6 kHz full-width-at-half-maximum (FWHM) at an output power of 62 mW and less than 50 kHz FWHM short term (10 µs) linewidth including technical noise. An upgraded version will provide an overall tuneability of 100 GHz and continous tuneability in excess of 20 GHz.

Small linewidths 76× nm DFB-laser diodes with optimised two-step epitaxial gratings

We present DFB laser diodes emitting in the 76x nm wavelengths range and focus on design and fabrication of the integrated Bragg gratings. Grating functionality is obtained with a periodically patterned GaAs0.75P0.25 layer with a thickness of 13 nm. We applied scanning transmission electron microscopy using a high angle annular dark-field detector for the analysis of the buried grating structures and for the improvement of the etching and regrowth conditions. Ridge waveguide DFB lasers with optimized gratings and production process show single mode emission with intrinsic linewidths below 10 kHz. Coated 1.5 mm long ridge waveguide DFB lasers emit stable over 5000 hours at a constant power of 100 mW.

Modular assembly of diode lasers in a compact and reliable setup for a wide range of applications

In the development process towards an integration of laser systems into compact modules many key points can be simulated. Yet, a reliable and stable testing environment is needed for a deeper understanding of the system. We present the micro optical bench (MiOB) as an advanced platform for the hybrid micro integration of active and passive optical elements. The modular yet robust design enables the precise mounting of those elements with an accuracy of better than 1 μm. By examples of second harmonic generation, master oscillator power amplifier and external cavity diode laser modules a wide range of applications are addressed. Each module is used to highlight different aspects of the MiOB. Examples are the thermal design of the MiOB that allows the precise heating of selected components without influencing others, the robustness that can withstand different mechanical tests, and the overall stiffness that allows the high precision mounting of volume holographic Bragg gratings.

Hybrid-integrated ECDL for precision Rubidium spectroscopy in space

Compact, single-mode, narrow linewidth, and continuously tuneable diode lasers find important application in optical metrology and atomic physics [1]. Currently, activities are moving towards carrying out quantum optics precision experiments under zero-gravity conditions [2] of a drop tower or in space. These experiments require lasers that meet the spectroscopic needs but simultaneously can operate reliably under the harsh conditions of a deployment in space.

Investigations of external cavity diode lasers: Simulations, analysis and experiments

We report the results of numerical and experimental investigations of the dynamics in an external cavity diode laser device composed of a semiconductor laser and a distant Bragg grating, which provides an optical feedback. The traveling wave model was used to simulate and analyze the nonlinear dynamics of the considered laser device. Finally, it is shown, that the simulation results are in good agreement with experiments.