Claus Braxmaier
A5073530875- Advanced Frequency and Time Standards
- Cold Atom Physics and Bose-Einstein Condensates
- Atomic and Subatomic Physics Research
- Geophysics and Sensor Technology
- Advanced Measurement and Metrology Techniques
- Advanced Fiber Laser Technologies
- Scientific Measurement and Uncertainty Evaluation
- Geophysics and Gravity Measurements
- Spectroscopy and Laser Applications
- Mechanical and Optical Resonators
- Adaptive optics and wavefront sensing
- Quantum Mechanics and Applications
- Advanced MEMS and NEMS Technologies
- Plasma Diagnostics and Applications
- Pulsars and Gravitational Waves Research
- Laser Design and Applications
- GNSS positioning and interference
- Inertial Sensor and Navigation
- Noncommutative and Quantum Gravity Theories
- Planetary Science and Exploration
- Spacecraft and Cryogenic Technologies
- Photonic and Optical Devices
- Advanced Fiber Optic Sensors
- Spacecraft Design and Technology
- Calibration and Measurement Techniques
Deutsches Zentrum für Luft- und Raumfahrt e. V. (DLR)
2015-2024
Universität Ulm
2021-2024
Center for Integrated Quantum Science and Technology
2022-2023
University of Bremen
2013-2022
SpaceTech (Germany)
2013-2022
Humboldt-Universität zu Berlin
2003-2019
Applied Photonics (United Kingdom)
2019
Institute for Applied Systems Technology Bremen
2014-2018
HTWG Hochschule Konstanz - Technik, Wirtschaft und Gestaltung
2006-2018
Dornier Flugzeugwerke (Germany)
2006-2009
The Laser Ranging Interferometer (LRI) instrument on the Gravity Recovery and Climate Experiment (GRACE) Follow-On mission has provided first laser interferometric range measurements between remote spacecraft, separated by approximately 220 km. Autonomous controls that lock frequency to a cavity reference establish 5 degrees of freedom two-way link spacecraft succeeded attempt. Active beam pointing based differential wave front sensing compensates attitude fluctuations. LRI operated...
The theory of general relativity describes macroscopic phenomena driven by the influence gravity while quantum mechanics brilliantly accounts for microscopic effects.Despite their tremendous individual success, a complete unification fundamental interactions is missing and remains one most challenging important quests in modern theoretical physics.The STE-QUEST satellite mission, proposed as medium-size mission within Cosmic Vision program European Space Agency (ESA), aims testing with high...
We report on a new test of Lorentz invariance performed by comparing the resonance frequencies two orthogonal cryogenic optical resonators subject to Earth's rotation over $\ensuremath{\sim}1\text{ }\mathrm{y}\mathrm{r}$. For possible anisotropy speed light $c$, we obtain ${\ensuremath{\Delta}}_{\ensuremath{\theta}}c/{c}_{0}=(2.6\ifmmode\pm\else\textpm\fi{}1.7)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}15}$. Within Robertson-Mansouri-Sexl (RMS) theory, this implies an isotropy...
Do the laws of quantum physics still hold for macroscopic objects - this is at heart Schrödinger's cat paradox or do gravitation yet unknown effects set a limit massive particles? What fundamental relation between and gravity? Ground-based experiments addressing these questions may soon face limitations due to limited free-fall times quality vacuum microgravity. The proposed mission Macroscopic Quantum Resonators (MAQRO) overcome allow such questions. MAQRO harnesses recent developments in...
We study a space-based gravity gradiometer based on cold atom interferometry and its potential for the Earth's gravitational field mapping. The instrument architecture has been proposed in [Carraz et al., Microgravity Science Technology 26, 139 (2014)] enables high-sensitivity measurements of gradients by using interferometers differential accelerometer configuration. present design including subsystems analyze mission scenario, which we derive expected performances, requirements sensor key...
Abstract We summarise the discussions at a virtual Community Workshop on Cold Atoms in Space concerning status of cold atom technologies, prospective scientific and societal opportunities offered by their deployment space, developments needed before atoms could be operated space. The technologies discussed include atomic clocks, quantum gravimeters accelerometers, interferometers. Prospective applications metrology, geodesy measurement terrestrial mass change due to, e.g., climate change,...
The LISA Technology Package (LTP), to be launched by ESA in 2006/2007, is a technology demonstration mission preparation for the space-borne gravitational wave detector. A central part of LTP optical metrology package (heterodyne interferometer with phasemeter) which monitors distance between two test masses noise level 10 pm Hz−1/2 3 mHz and 30 mHz. It has dynamic range >100 µm without any actuators pathlength. In addition longitudinal measurements, it provides alignment measurements an...
We report on a compact and ruggedized setup for laser frequency stabilization employing Doppler-free spectroscopy of molecular iodine near 532 nm. Using 30 cm long cell in triple-pass configuration combination with noise-canceling detection residual amplitude modulation control, instability 6×10-15 at 1 s integration time Flicker noise floor below 3×10-15 times between 100 1000 was found. A specific assembly-integration technology applied the realization setup, ensuring high beam pointing...
The development of compact optical frequency references plays an important role in future timing systems, on the ground and space, including next-generation global-navigation satellite systems. Realization qualification such systems is held back by technical challenges creating robust, reliable devices for metrology under demanding conditions. Here researchers demonstrate autonomous operation I${}_{2}$ reference measurement its using a dual comb sounding rocket, as milestone way to routine...
Abstract Future generations of global navigation satellite systems (GNSSs) can benefit from optical technologies. Especially clocks could back-up or replace the currently used microwave clocks, having potential to improve GNSS position determination enabled by their lower frequency instabilities. Furthermore, clock technologies—in combination with inter-satellite links—enable new architectures, e.g., synchronization distant references within constellation using time and transfer techniques....
Microgravity eases several constraints limiting experiments with ultracold and condensed atoms on ground. It enables extended times of flight without suspension eliminates the gravitational sag for trapped atoms. These advantages motivated numerous initiatives to adapt operate experimental setups microgravity platforms. We describe design payload, motivations choices, capabilities Bose-Einstein Condensate Cold Atom Laboratory (BECCAL), a NASA-DLR collaboration. BECCAL builds heritage...
A 190-day comparison of the optical frequencies defined by an cavity and a molecular electronic transition is analyzed for velocity independence speed light (Kennedy-Thorndike test) universality gravitational redshift. The modulation laboratory potential were provided Earth's orbital motion around Sun. We find velocity-dependence coefficient (1.9+/-2.1)x10(-5), 3 times lower compared to best previous test. Alternatively, data confirm redshift at 4% level. Prospects significant improvements...
We report on the development of LISA Technology Package (LTP) experiment that will fly onboard Pathfinder mission European Space Agency in 2008. first summarize science rationale aimed at showing operational feasibility so-called transverse–traceless coordinate frame within accuracy needed for LISA. then show briefly basic features instrument and we finally discuss its projected sensitivity extrapolation results to
The Laser Interferometer Space Antenna (LISA) aims at detecting gravitational waves by referencing heterodyne interferometry to free-flying (inertial) proof masses, located the corners of a triangle with 5 million kilometers arm length. position each mass respect associated satellite must be measured 1 pm Hz−1/2-sensitivity in translation measurement and below 10 nrad attitude. In this paper, we present compact interferometer utilizing polarizing optics combined method differential wavefront...
Frequency combs downconvert absolute optical frequency references and thereby can significantly advance time precision in satellite-based navigation systems, fundamental science, earth observation, many other spaceborne applications. We have developed a compact vacuum compatible double comb system, minimizing volume, mass, power consumption compared to its precursor. Apart from redundancy aspects, the two enable autonomous mode number determination. Here, we report on space system design...
Within the model of a Lorentz violating extension Maxwell sector standard model, modified light propagation leads to change resonance frequency an electromagnetic cavity, allowing cavity tests violation. However, is also affected by material-dependent length due Coulomb potential arising from same violation as well. We derive taking both into account. The new effects derived are negligible for present experiments, but will be more pronounced in future using novel resonator materials.
BOOST (BOOst Symmetry Test) is a proposed space mission to search for Lorentz invariance violations and aims improve the Kennedy-Thorndike parameter constraint by two orders of magnitude.The consists comparing optical frequency references different nature, an cavity hyperfine transition in molecular iodine, low Earth orbit.Naturally, stability at orbit period 5400 s (f =0.18 mHz) essential success.Here we present our experimental efforts achieve required fractional 7.4 × 10 -14 Hz -1/2 0.18...
Gravitational Waves (GWs) were observed for the first time in 2015, one century after Einstein predicted their existence. There is now growing interest to extend detection bandwidth low frequency. The scientific potential of multi-frequency GW astronomy enormous as it would enable obtain a more complete picture cosmic events and mechanisms. This unique entirely new opportunity future astronomy, success which depends upon decisions being made on existing infrastructures. prospect combining...
The interferometer of the LISA technology package (LTP) on SMART-2 is needed to verify performance gravitational sensors by monitoring distance between two test masses with a noise level 10 pm Hz -1/2 3 mHz and 30 mHz.It must continuously track motion mass while that changes many µm speed up 20 s -1 , without losing sign exerting any influence might lead above level.As result detailed comparison study, heterodyne Mach-Zehnder was selected as baseline for mission.Its design expected are...