6,742 research outputs found
Stabilized high-power laser system for the gravitational wave detector advanced LIGO
An ultra-stable, high-power cw Nd:YAG laser system, developed for the ground-based gravitational wave detector Advanced LIGO (Laser Interferometer Gravitational-Wave Observatory), was comprehensively characterized. Laser power, frequency, beam pointing and beam quality were simultaneously stabilized using different active and passive schemes. The output beam, the performance of the stabilization, and the cross-coupling between different stabilization feedback control loops were characterized and found to fulfill most design requirements. The employed stabilization schemes and the achieved performance are of relevance to many high-precision optical experiments
Laser power stabilization for second-generation gravitational wave detectors
We present results on the power stabilization of a Nd:YAG laser in the frequency band from 1 Hz to 100 kHz. High-power, low-noise photodetectors are used in a dc-coupled control loop to achieve relative power fluctuations down to 5×10−9 Hz−1/2 at 10 Hz and 3.5×10−9 Hz−1/2 up to several kHz, which is very close to the shot-noise limit for 80 mA of detected photocurrent on each detector. We investigated and eliminated several noise sources such as ground loops and beam pointing. The achieved stability level is close to the requirements for the Advanced LIGO gravitational wave detector
Stabilized lasers for advanced gravitational wave detectors
Second generation gravitational wave detectors require high power lasers with more than 100 W of output power and with very low temporal and spatial fluctuations. To achieve the demanding stability levels required, low noise techniques and adequate control actuators have to be part of the high power laser design. In addition feedback control and passive noise filtering is used to reduce the fluctuations in the so-called prestabilized laser system (PSL). In this paper, we discuss the design of a 200 W PSL which is under development for the Advanced LIGO gravitational wave detector and will present the first results. The PSL noise requirements for advanced gravitational wave detectors will be discussed in general and the stabilization scheme proposed for the Advanced LIGO PSL will be described
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
Stabilized High Power Laser for Advanced Gravitational Wave Detectors
Second generation gravitational wave detectors require high power lasers with several 100W of output power and with very low temporal and spatial fluctuations. In this paper we discuss possible setups to achieve high laser power and describe a 200W prestabilized laser system (PSL). The PSL noise requirements for advanced gravitational wave detectors will be discussed in general and the stabilization scheme proposed for the Advanced LIGO PSL will be described. Special emphasis will be given to the most demanding power stabilization requiremets and new results (RIN ≤ 4×10-9/surdHz) will be presented
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Laser and electron deflection from transverse asymmetries in laser-plasma accelerators.
We report on the deflection of laser pulses and accelerated electrons in a laser-plasma accelerator (LPA) by the effects of laser pulse front tilt and transverse density gradients. Asymmetry in the plasma index of refraction leads to laser steering, which can be due to a density gradient or spatiotemporal coupling of the laser pulse. The transverse forces from the skewed plasma wave can also lead to electron deflection relative to the laser. Quantitative models are proposed for both the laser and electron steering, which are confirmed by particle-in-cell simulations. Experiments with the BELLA Petawatt Laser are presented which show controllable 0.1-1 mrad laser and electron beam deflection from laser pulse front tilt. This has potential applications for electron beam pointing control, which is of paramount importance for LPA applications
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