Bose-Einstein Condensation in Microgravity van Zoest, T; Gaaloul, N; Singh, Y ...
Science (American Association for the Advancement of Science),
06/2010, Letnik:
328, Številka:
5985
Journal Article
Recenzirano
Albert Einstein's insight that it is impossible to distinguish a local experiment in a "freely falling elevator" from one in free space led to the development of the theory of general relativity. The ...wave nature of matter manifests itself in a striking way in Bose-Einstein condensates, where millions of atoms lose their identity and can be described by a single macroscopic wave function. We combine these two topics and report the preparation and observation of a Bose-Einstein condensate during free fall in a 146-meter-tall evacuated drop tower. During the expansion over 1 second, the atoms form a giant coherent matter wave that is delocalized on a millimeter scale, which represents a promising source for matter-wave interferometry to test the universality of free fall with quantum matter.
Atom interferometers covering macroscopic domains of space-time are a spectacular manifestation of the wave nature of matter. Because of their unique coherence properties, Bose-Einstein condensates ...are ideal sources for an atom interferometer in extended free fall. In this Letter we report on the realization of an asymmetric Mach-Zehnder interferometer operated with a Bose-Einstein condensate in microgravity. The resulting interference pattern is similar to the one in the far field of a double slit and shows a linear scaling with the time the wave packets expand. We employ delta-kick cooling in order to enhance the signal and extend our atom interferometer. Our experiments demonstrate the high potential of interferometers operated with quantum gases for probing the fundamental concepts of quantum mechanics and general relativity.
We report on the realization of distributed Bragg reflector laser diodes emitting near a wavelength of 1064 nm in a single longitudinal mode with high output power and kHz-level intrinsic spectral ...linewidth. Linewidth measurements are performed with a heterodyne measurement setup in which both lasers are weakly locked to each other in order to reject slow frequency drifts. The linewidth is analyzed in dependence of the output power. The FWHM linewidth is almost independent from the output power and corresponds to approximately 180 kHz whereas the intrinsic linewidth decreases with a 1/
P
out
dependence. The minimum intrinsic linewidth is 2 kHz at an output power of 180 mW. The measured intrinsic linewidth is in good correspondence with a theoretical estimation.
We present a micro-integrated extended cavity diode laser module for experiments on rubidium Bose–Einstein condensates and atom interferometry at 780.24 nm onboard a sounding rocket. The ...micro-integration concept is optimized for space application. The laser chip, micro-lenses, a volume holographic Bragg grating, micro-temperature sensors and a micro-thermoelectric cooler are integrated on an aluminium nitride ceramic micro-optical bench with a foot print of only 50 × 10 mm
2
. Moveable parts are omitted to allow for a very compact and robust design. The laser module provides an output power of more than 120 mW at a short term (170 μs) linewidth of 54 kHz, both full-width-at-half-maximum. The laser can be coarsely tuned by 44 GHz with a continuous tuning range of 31 GHz. The micro-integration technology presented here can be transferred to other wavelengths.
We experimentally demonstrate the possibility of preparing ultracold atoms in the environment of weightlessness at the earth-bound short-term microgravity laboratory Drop Tower Bremen, a facility of ...ZARM -- University of Bremen. Our approach is based on a freely falling magneto-optical trap (MOT) drop tower experiment performed within the ATKAT collaboration ('Atom-Catapult') as a preliminary part of the QUANTUS pilot project ('Quantum Systems in Weightlessness') pursuing a Bose--Einstein condensate (BEC) in microgravity at the drop tower 1, 2. Furthermore we give a complete account of the specific drop tower requirements to realize a compact and robust setup for trapping and cooling neutral rubidium 87Rb atoms in microgravity conditions. We also present the results of the first realized freely falling MOT and further accomplished experiments during several drops.
Compact laser sources with long coherence lengths in the visible spectral region are sought for many applications. This letter presents distributed-Bragg-reflector (DBR) ridge-waveguide (RW) lasers ...with an emission wavelength at 633 nm and an optical output power >20 mW. The DBR-RW lasers exhibit a technical linewidth at full width at half maximum of ~1 MHz. The emission line can be tuned via current and temperature >200 GHz. At 14 mW, the lasers show a preliminary lifetime 4000 h.
We demonstrate the realization of narrow linewidth, high-power ridge waveguide DFB diode lasers emitting near 780 nm. The effects of the coupling coefficient, the laser chip length, and the ...fabrication process onto the spectral linewidth are discussed. By optimizing both the cavity length and the coupling coefficient, we achieve an intrinsic spectral linewidth as small as 35 kHz at an output power of 270 mW.
Future projects for fundamental research with atom interferometry in space demand for compact and robust laser systems. We present highly integrated diode laser based systems for high precision ...matter wave interferometry experiments in microgravity.
We present a micro-integrated master-oscillator-power-amplifier diode laser system with more than 1W output power at 780.2 nm and narrow linewidth emission. The laser is designed for Rubidium ...Bose-Einstein condensate experiments in space.
We report on the realization of a semiconductor laser based master oscillator power amplifier (MOPA) system with high output power and narrow linewidth. The system features an output power of more ...than 1 W in stable single mode operation. The FWHM linewidth is 100 kHz and the minimum intrinsic linewidth is as small as 3.6 kHz. The laser concept presented here may find application in coherent optical communication, specifically in space, or within future precision spectroscopy and quantum optics experiments in harsh environments.
PDF
