193 research outputs found
Analytical description of interference between two misaligned and mismatched complete Gaussian beams
A typical application for laser interferometers is a precision measurement of
length changes that result in interferometric phase shifts. Such phase changes
are typically predicted numerically, due to the com- plexity of the overlap
integral that needs to be solved. In this paper we will derive analytical
representations of the interferometric phase and contrast (aka. fringe
visibility) for two beam interferometers, both homodyne and heterodyne. The
fundamental Gaussian beams can be arbitrarily misaligned and mismatched to each
other. A limitation of the analytical result is that both beams must be
detected completely, which can experimentally be realized by a sufficiently
large single-element photodetector.Comment: 8 pages, 2 figure
First stage of LISA data processing: Clock synchronization and arm-length determination via a hybrid-extended Kalman filter
In this paper, we describe a hybrid-extended Kalman filter algorithm to
synchronize the clocks and to precisely determine the inter-spacecraft
distances for space-based gravitational wave detectors, such as (e)LISA.
According to the simulation, the algorithm has significantly improved the
ranging accuracy and synchronized the clocks, making the phase-meter raw
measurements qualified for time- delay interferometry algorithms.Comment: 14 pages, Phys. Rev. D 90, 064016 (2014
First stage of LISA data processing II: Alternative filtering dynamic models for LISA
Space-borne gravitational wave detectors, such as (e)LISA, are designed to
operate in the low-frequency band (mHz to Hz), where there is a variety of
gravitational wave sources of great scientific value. To achieve the
extraordinary sensitivity of these detector, the precise synchronization of the
clocks on the separate spacecraft and the accurate determination of the
interspacecraft distances are important ingredients. In our previous paper
(Phys. Rev. D 90, 064016 [2014]), we have described a hybrid-extend Kalman
filter with a full state vector to do this job. In this paper, we explore
several different state vectors and their corresponding (phenomenological)
dynamic models, to reduce the redundancy in the full state vector, to
accelerate the algorithm, and to make the algorithm easily extendable to more
complicated scenarios.Comment: 12 page
Vanishing tilt-to-length coupling for a singular case in two-beam laser interferometers with Gaussian beams
The omnipresent tilt-to-length coupling in two-beam laser interferometers,
frequently a nuisance in precision measurements, vanishes for the singular case
of two beams with identical parameters and complete detection of both beams
without clipping. This effect has been observed numerically and is explained in
this manuscript by the cancellation of two very different effects of equal
magnitude and opposite sign.
This paper was published in Applied Optics and is made available as an
electronic reprint with the permission of OSA. The paper can be found at the
following URL on the OSA website:
[http://www.opticsinfobase.org/ao/abstract.cfm?URI=ao-54-5-1010]. Systematic or
multiple reproduction or distribution to multiple locations via electronic or
other means is prohibited and is subject to penalties under law
A DC-Coupled, HBT-Based Transimpedance Amplifier for the LISA Quadrant Photoreceivers
[For abstract see PDF
Sub-pm/ non-reciprocal noise in the LISA backlink fiber
The future space-based gravitational wave detector Laser Interferometer Space
Antenna (LISA) requires bidirectional exchange of light between its two optical
benches on board of each of its three satellites. The current baseline foresees
a polarization-maintaining single-mode fiber for this backlink connection.
Phase changes which are common in both directions do not enter the science
measurement, but differential ("non-reciprocal") phase fluctuations directly do
and must thus be guaranteed to be small enough. We have built a setup
consisting of a Zerodur baseplate with fused silica components
attached to it using hydroxide-catalysis bonding and demonstrated the
reciprocity of a polarization-maintaining single-mode fiber at the 1
pm/ level as is required for LISA. We used balanced
detection to reduce the influence of parasitic optical beams on the reciprocity
measurement and a fiber length stabilization to avoid nonlinear effects in our
phase measurement system (phase meter). For LISA, a different phase meter is
planned to be used that does not show this nonlinearity. We corrected the
influence of beam angle changes and temperature changes on the reciprocity
measurement in post-processing
Interferometry for LISA and LISA pathfinder
The Laser Interferometer Space Antenna (LISA) is a joint ESA-NASA mission designed to observe gravitational waves in the frequency range between 10 -4 to 1 Hz, where ground-based detectors are limited by terrestrial noise. Sources in this frequency range include supermassive black holes and galactic binary stars. LISA consists of three identical spacecraft separated by 5 million kilometers carrying a total of six free flying proof masses in heliocentric drag-free orbit. The fluctuations in separation between two test masses located in different satellites will be measured by laser interferometry with picometer precision. LISA Pathfinder is a technology demonstration mission for LISA consisting of only two test masses in one single satellite. It will be launched in 2009, five years before LISA. We provide here an overview of the development of LISA and LISA Pathfinder with particular emphasis on the interferometry
A brief comparison of optical pathlength difference and various definitions for the interferometric phase
To this paper we discuss that the phase readout in low noise laser interferometers can significantly deviate from the underlying optical pathlength difference (OPD). The cross coupling of beam tilt to the interferometric phase readout is compared to the OPD. For such a system it is shown that the amount of tilt to phase readout coupling depends strongly on the involved beams and their parameters, as well as on the detector properties and the precise definition of the phase. The unique single element photodiode phase is therefore compared to three common phase definitions for quadrant diodes. It is shown that neither phase definition globally shows the least amount of cross coupling of angular itDeutsches Zentrum fĂĽr Luft- und Raumfahrt (DLR)/No 50 OQ 130
Disturbances from Single Event Upsets in the GRACE Follow-On Laser Ranging Interferometer
The Gravity Recovery And Climate Experiment - Follow On (GRACE-FO) satellite
mission (2018-now) hosts the novel Laser Ranging Interferometer (LRI), a
technology demonstrator for proving the feasibility of laser interferometry for
inter-satellite ranging measurements. The GRACE-FO mission extends the valuable
climate data record of changing mass distribution in the system Earth, which
was started by the original GRACE mission (2002-2017). The mass distribution
can be deduced from observing changes in the distance of two low-earth orbiters
employing interferometry of electromagnetic waves in the K-Band for the
conventional K-Band Ranging (KBR) and in near-infrared for the novel LRI. This
paper identifies possible radiation-induced Single Event Upset (SEU) events in
the LRI phase measurement. We simulate the phase data processing within the
Laser Ranging Processor (LRP) and use a template-based fitting approach to
determine the parameters of the SEU and subtract the events from the ranging
data. Over four years of LRI data, 29 of such events were identified and
characterized
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