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LISA Experimental I (Ballroom B/C)
Tuesday Chair: Hubert Halloin
13:30 - 13:50 Ewan Fitzsimons
Airbus DS
eLISA Technology Consolidation Study
13:50 - 14:05 Simon Barke
Albert Einstein Institute, Max Planck Institute for Gravitational Physics, Leibniz Universität Hannover
The European LISA Metrology System #1: Conceptual Design Choices and the Frequency Distribution Subsystem
14:05 - 14:20 Oliver Gerberding
Albert Einstein Institute, Max Planck Institute for Gravitational Physics, Leibniz Universität Hannover
The European LISA Metrology System #2: Phasemeter Breadboard and the Optical TestbedDownload
14:20 - 14:35 Gang Jin
Institute of Mechanics, Chinese Academy of Science
Development of laser interferometer prototype used for satellite-to-satellite displacement measurementDownload
14:35 - 14:50 Michael Perreur-Lloyd
University of Glasgow
Sub-system mechanical design for an eLISA optical benchDownload
14:50 - 15:05 Pierre Gruning
University Paris-Diderot/APC Laboratory
An electro-optical simulator for eLISA : Lisa On Table (LOT)Download
15:05 - 15:20 Jeffrey Livas
NASA Goddard Space Flight Center
Gravitational wave optical telescope design study resultsDownload
15:20 - 15:35 Jordan Camp
NASA / Goddard Space Flight Center
Development of a US Gravitational Wave Laser System for LISADownload
eLISA Technology Consolidation Study
Ewan Fitzsimons - Airbus DS
Ewan Fitzsimons, Nico Brandt, Ulrich Johann, Hans-Reiner Schulte, Dennis Weise and Tobias Ziegler. In preparation for an L2/L3 mission definition phase later in the decade, DLR has awarded a "Technology Consolidation" study to Astrium Satellites Germany (now Airbus DS) as part of its eLISA technology development program at AEI Hannover. The purpose of this study is to review the trades and to further advance the design options that were identified during the brief NGO Reformulation and earlier LISA studies and to identify possible areas of technology development which should be targeted in the lead-up to a potential mission definition phase later in the decade. We will give a brief overview of the study and provide details on some of the most interesting results.
The European LISA Metrology System #1: Conceptual Design Choices and the Frequency Distribution Subsystem
Simon Barke - Albert Einstein Institute, Max Planck Institute for Gravitational Physics, Leibniz Universität Hannover
One of the core technologies for future LISA-like space-based gravitational wave detectors is shot-noise limited heterodyne laser interferometry at frequencies between 0.1 mHz and 1 Hz. To reach the required precision, algorithms extract precise timing information from the data streams in preparation for time delay interferometry. Here a virtual interferometer free from technical noise sources such as laser frequency noise and sampling clock timing jitter is formed. Within the scope of an ESA technology development activity a breadboard model of the frequency distribution subsystem (FDS) was designed, built and tested successfully by a consortium consisting of the Danish National Space Institute, the Danish industry partner Axcon Aps. and the German Albert Einstein Institute. As part of the LISA metrology system, the FDS provides all required data streams for precise timing and technical noise suppression, and plays a key role in enabling a shot-noise limited LISA performance. In this talk, noise suppression techniques are presented and conceptual design choices of the LISA metrology system are explained. Furthermore we will present the breadboard model of the frequency distribution subsystem which achieved full performance and functionality.
The European LISA Metrology System #2: Phasemeter Breadboard and the Optical Testbed Download
Oliver Gerberding - Albert Einstein Institute, Max Planck Institute for Gravitational Physics, Leibniz Universität Hannover
The interferometric signals of LISA-like missions contain the gravitational wave signals, as well as additional information that is required for auxilliary functions which in turn are necessary to achieve a shot-noise limited performance. The LISA phasemeter is one of the core components of LISA and performs the readout and control of all of these signal components. The functionalities of the phasemeter therefore cover the science phase readout with urad/sqrt(Hz) precision, clock tone transfer and inter-spacecraft ranging for the supression of technical noise sources, laser frequency control, realtime angular readout and the inital beatnote acquisition. Within the scope of an ESA technology development activity a breadboard model of the LISA phasemeter was designed, built and tested successfully by a consortium consisting of the Danish National Space Institute, the Danish industry partner Axcon Aps. and the German Albert Einstein Institute. In the first part of this talk we will present the breadboard itself and the results of this activity, where we were able to achieve all performance requirements and demonstrated all required functionalities. In the second part of the talk we will decribe the testbed that we use to perform integrated optical tests with the breadboard. It allows us to investigate the performance under realistic conditions including the behaviour of photodiodes and signals at different frequencies, which will give insight into the noise, as well as the non-linearities of the system. In an extend scheme of our testbed we will also include clock-noise transfer, via the frequency distribution system, making it possible to test the combination of high dynamic range phase measurements and clock noise correction, which is essential for performing the TDI algorithm in LISA.
Development of laser interferometer prototype used for satellite-to-satellite displacement measurement Download
Gang Jin - Institute of Mechanics, Chinese Academy of Science
China has been starting to develop an independent space Gravitational Wave G.W. detection mission ever since 2008. In 2011, Chinese Academy of Sciences (CAS) and European Space Agency (ESA) discussed a possibility on bilateral collaboration for eLISA or NGO. To fulfil the commitments of Chinese part, a twin satellite mission to demonstrate the technology for space G.W. detection is proposed. In order to develop Chinese space G.W. detection mission and prepare for the possible collaboration with ESA, a Chinese space G.W. detection working group of Chinese Academy of Sciences is constituted in 2012. Institute of Mechanics (IMECH) of CAS is assigned to develop the laser metrology system. A prototype of laser displacement measurement system with the design of equal arm-length Mach-Zehnder interferometer used for the technology demonstration satellite mission has been constructed. Therefore, even with a very noisy laser source, 1MHz/Hz1/2 frequency instability, a sensitivity of 100 pm/Hz1/2 is achieved in the frequency band from 1mHz to 1Hz. Several key techniques, including the phase-meter and beam pointing control, has been also installed within this prototype, the phase-meter precision of 2×10-5 rad/Hz1/2 and the beam pointing control stability of 100 nrad/Hz1/2is realized.
Sub-system mechanical design for an eLISA optical bench Download
Michael Perreur-Lloyd - University of Glasgow
We present the design and development status of the opto-mechanical sub-systems that will be used for the experimental demonstration of imaging systems for eLISA. On to a Zerodur® optical bench we incorporate lenses, photodetectors, and other opto-mechanics that have to be both adjustable - with an accuracy of a few microns - and stable over a 0 to 40°C temperature range. The alignment of a multi-lens imaging system and the characterisation of the system in multiple degrees of freedom is particularly challenging. We will describe the mechanical design of the precision mechanisms, including thermally stable flexure-based optical mounts and complex multi-lens, multi-axis adjuster mechanisms, and update on the integration of the mechanisms on the optical bench.
An electro-optical simulator for eLISA : Lisa On Table (LOT) Download
Pierre Gruning - University Paris-Diderot/APC Laboratory
Understanding phase noise sources and efficiency of noise reduction methods on realistic data is of crucial importance for eLISA. For that purpose, an electro-optical simulator for long arm interferometry is being developed at the APC laboratory in Paris, France. This simulator combines optical and electronic interferometers in order to identify the intrinsic noise level of each component of the simulator. The generation of the noise is computer controlled to simulate realistic propagation delays, Doppler effects and noise characteristics. The generated noise is injected into the interferometers using direct digital synthesizers and the readout performed using the phasemeter developed by the AEI in Hanover. Performance of noise-reduction algorithm (such as Time Delay Interferometry) can then be tested on representative frequency records. Currently the experiment simulates two satellites, each one using a local arm and two distant arms disposition. The present configuration demonstrated a 4.10^7 reduction factor, limited by the residual optical phase noise of the interferometer. The present status of the experiment and the first measurement's results will be presented, as well as the foreseen work aiming at reducing the residual interferometer noises, such as active path length compensation. Further enhancements to complete the simulator as a third satellite to get closer to eLISA configuration will also be part of the presentation.
Gravitational wave optical telescope design study results Download
Jeffrey Livas - NASA Goddard Space Flight Center
We report on the results of a study conducted from Nov 2012-Apr 2013 by an industrial contractor to develop a telescope design for a space-based gravitational wave detector. The telescope is needed for efficient power delivery but since it is directly in the beam path, the design is driven by the requirements for the displacement sensitivity of the gravitational wave observatory. Two requirements in particular, optical pathlength stability and scattered light performance, are beyond the usual specifications for good image quality encountered in traditional telescopic systems. An important element of the study was to tap industrial expertise to develop an optimized design that can be reliably manufactured. Key engineering and design trade-offs and the sometimes surprising results will be presented. Finally we report on initial efforts to procure mirrors to be integrated into an experimental test-bed for the design.
Development of a US Gravitational Wave Laser System for LISA Download
Jordan Camp - NASA / Goddard Space Flight Center
A highly stable and robust laser system is a key component of the space-based LISA mission architecture. In this talk I will describe our plans to demonstrate a TRL 5 LISA laser system at Goddard Space Flight Center by 2016. The laser system includes a low-noise oscillator followed by a power amplifier. The oscillator is a low-mass, compact 10 mW External Cavity Laser, consisting of a semiconductor laser coupled to an optical cavity, built by the laser vendor Redfern Integrated Optics. The amplifier is a diode-pumped Yb fiber with 2W output, built at Goddard. I will show noise and reliability data for the full laser system, and describe our plans to reach TRL 5 by 2016.