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Elise Van den Bossche (Vrije Universiteit Brussel)High PowerPoster
The ETpathfinder research facility in Maastricht is dedicated to developing key technologies for the Einstein Telescope (ET). By implementing these in a 10 m prototype cryogenic interferometer, the facility aims to investigate and validate their performance and compatibility within an ET-like environment.
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One such technology is a novel 1550 nm laser source, developed by the Max Planck... -
Chunnong Zhao (University of Western Australia)Optical DesignPoster
AlGaAs/GaAs crystalline coatings are promising for future gravitational-wave detectors due to their low mechanical loss and superior optical properties. However, their high optical absorption at 532 nm precludes the use of conventional arm-length stabilization schemes based on 532 nm auxiliary lasers.
We present an alternative arm-length stabilization scheme employing an auxiliary laser at...
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Saps Buchman (Stanford University)OtherPoster
We present a passive ultraviolet (UV) charge management system for the test masses (TMs) of ground-based laser interferometric gravitational wave detectors. The system uses photoelectron emission from low work-function gold coatings illuminated by 275–285 nm UV light to neutralize unwanted electric charges on the TMs, maintaining them at zero potential. Two implementation schemes are...
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Riccardo DesalvoLow Frequency NoisePoster
The force required on the mirrors for interferometer lock acquisition can be reduced below 0.25 mN if the pendulum modes are actively damped to levels below the Low Noise Peterson model. The required locking force can be applied using the rigid suspension beams as mechanical levers by mounting electrostatic actuators between the beam counterweights and the intermediate mass. This approach...
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Luca Massaro (Maastricht University & Nikhef)Thermal noisePoster
Coating thermal noise limits the sensitivity of gravitational-wave detectors in the most sensitive frequency band. As third-generation detectors, like the Einstein Telescope or LIGO Voyager, advance toward cryogenic interferometers to reduce thermal noise, current coating materials such as Ta$_{2}$O$_{5}$ and SiO$_{2}$ become inadequate due to their high mechanical loss at low temperatures....
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Chiaki Hirose (Institute for Cosmic Ray Research, The University of Tokyo)Optical DesignPoster
Precise alignment sensing and control are essential for the stable operation of laser interferometric gravitational-wave detectors. In conventional Wave Front Sensing (WFS) based on the beat between the carrier and phase-modulated (PM) sidebands, signals from the arm cavity axis dominate when the carrier resonates throughout the interferometer, making it difficult to detect signals from other...
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Julia Casanueva Diaz (EGO)Optical DesignPoster
To further reduce thermal noise in future detectors, and depending on progress in the development of improved coating materials, it will be important to adapt the optical design of the Fabry–Perot arm cavities to optimize the beam size. However, in current gravitational-wave detectors, the geometry of the central interferometer is constrained by the available space and stability requirements....
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Marc Eisenmann (NAOJ)Exploring new directionsPoster
In order to reduce thermal noise, KAGRA operates at cryogenic temperatures with crystalline test-masses. The non-uniform birefringence of these test-masses distorts the beam circulating in the detector and can limit the detector’s sensitivity. These issues could be even more severe for future generation of detectors with larger crystalline test-masses.
In this talk, we will report our...
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Peter Carney (California Institute of Technology)Quantum NoisePoster
With quantum squeezing emerging as an essential technology for gravitational wave detectors and quantum metrology, there are ongoing efforts to develop compact broadband sources. We report over −3.0 dB of broadband squeezing at 1064 nm using a periodically-poled lithium niobate (PPLN) waveguide crystal. Using a single pass through the waveguide, squeezing is observed from the MHz range all the...
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Riccardo DesalvoLow Frequency NoisePoster
We present the conceptual design of a novel cryogenic silicon suspension for the Einstein Telescope’s low-frequency detector. The proposed configuration departs from traditional tension-dominated suspensions by employing rigid beams and short flexures operating under compressional load. This approach leverages silicon’s substantially higher compressive strength to achieve improved mechanical...
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Paul Fulda (University of Florida)Optical DesignPoster
In this poster I will describe the unique challenges for the optical design of the Cosmic Explorer interferometers, in many cases driven by the very long 40km arms. These challenges have led to novel design choices for the corner layout, and new requirements on many interferometer subsystems. I will describe the two leading corner layouts we have identified at this stage, as well as some of...
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Tobias Eckhardt (University of Hamburg)Low Frequency NoisePoster
Current gravitational wave detectors are limited by noises, at frequencies below 10 Hz, related to currently used local displacement sensors.
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In this poster we present our research on compact displacement sensors based on deep-frequency modulation interferometry (DFMI), for the local displacement measurement of test-masses, to overcome these limitations. -
Dr Sourath Ghosh (Max Planck Institute for Gravitational Physics, Hanover, Germany)Observatories in spacePoster
The Laser Interferometer Space Antenna (LISA) will be the first space-based gravitational-wave (GW) detector operating in the millihertz regime. To suppress the otherwise-dominant laser frequency noise and clock jitter, LISA relies on Time-Delay Interferometry (TDI) and clock-noise suppression algorithms applied in post-processing. While these techniques have been extensively studied through...
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Ryosuke Sugimoto (The University of Tokyo)Quantum NoisePoster
This research aims to realize an optomechanical system with sensitivity at the quantum noise level in the milligram mass range. Such systems are expected to be applied as demonstration platforms for quantum noise reduction technology and as macroscopic quantum systems for verifying fundamental physics. This research aims to measure the rotational modes of a torsion pendulum with quantum noise...
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Yuri Todoroki (University of Tokyo's Graduate School of Science)Thermal noisePoster
The Torsion-Bar Antenna (TOBA) is a ground-based gravitational wave detector sensitive to the low-frequency band of 0.1 Hz - 10 Hz. TOBA consists of two horizontally suspended bar-shaped test masses (torsion pendulums) and a laser interferometer. Gravitational waves can be observed by detecting the rotation of the torsion pendulums induced by the waves using the laser interferometer....
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Matteo Ianni (INFN, Section of Rome Tor Vergata, Rome, Italy. University of Rome Tor Vergata, Department of Physics, Rome, Italy)High PowerPoster
Enhancing the sensitivity of gravitational-wave detectors represents a major challenge that requires stable operation at increasingly high optical power. Optical absorption within Fabry–Pérot cavities induces thermal aberrations that, if not properly compensated, can significantly degrade the interferometer performance. The active correction of these effects in present-day and next-generation...
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Anna Green (Nikhef, Maastricht University), Mikhail Korobko (University of Hamburg)Optical DesignPoster
We present the current optical layouts (10km Triangle and 15km L) proposed for the Einstein Telescope, as developed during the 2025 detector design Task Force and discussed in talk #45.
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Takaaki Yokozawa (ICRR, University of Tokyo, Japan)Low Frequency NoisePoster
KAGRA is a kilometer-scale gravitational-wave interferometer located in Japan. It has two unique features: a cryogenic environment and an underground site. KAGRA joined the O4c observing run in July 2026 with a binary neutron star merger range of 7.5 Mpc. In this talk, we present an evaluation of various environmental noise sources affecting the KAGRA detector, with a particular focus on...
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Dr Michael HARTMAN (Institut Fresnel; Université de Aix-Marseille)Thermal noisePoster
From the 10 cm optical cavities used to reference ultra-stable lasers to the 3 km arm cavities of interferometric gravitational-wave detectors, precision optical experiments have reached a fundamental performance limit: mirror thermal-noise. In the context of gravitational-wave detection, planned observatory upgrades aim for a decrease in mirror coating thermal-noise, where in particular, the...
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Munetake Otsuka (U-Tokyo / NAOJ / KEK)Thermal noisePoster
Thermal noise from suspension systems is one of the fundamental noise sources limiting the sensitivity of gravitational-wave detectors. The mechanical loss of suspension fibers supporting the test masses can contribute significantly to suspension thermal noise, particularly in cryogenic detectors such as KAGRA, where the mirrors are cooled through the suspension fibers. Accurate measurements...
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Sophie Muusse (University of Adelaide)Optical DesignPoster
High power cavity systems require sophisticated thermal compensation systems to maintain resonant fields while the mirrors experience significant thermal actuation. The efficacy of these systems is limited by the ability to understand and model these effects. aLIGO's thermal model has previously been unable to accurately predict the thermal state, impeding the improvement of these systems and...
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Riccardo DesalvoLow Frequency NoisePoster
A variety of benefits can be realized by eliminating large cavern halls in favor of a dual tunnel system. Additional benefits will come with the use of a small diameter vacuum vessel and cryostat, so-called “reach in” vs. “walk in”. I will discuss motivating factors, safety, access, cost and stability. I will then show an animation demonstrating the feasibility of assembling the cryogenic...
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Preeti SharmaLow Frequency NoisePoster
Advanced LIGO detectors are susceptible to environmental disturbances, such as seismic activities by ocean waves, earthquakes, wind, and anthropogenic activities, which can significantly impact their operation and performance. Microseismic ground motion is a low-frequency (0.1-1.0 Hz) seismic motion that arises primarily from ocean waves and becomes particularly high during the winter months....
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Bin Wu (Syracuse University)Optical DesignPoster
Currently, the sensitivity of Gravitational Wave (GW) detection on Earth
is limited by the coating thermal noise. AlGaAs/GaAs crystalline coatings are
a promising coating candidate for the next generation of GW detectors, due to
their much lower thermal noise.In this poster, we investigate the birefringence properties of this crystalline semiconductor material by modulating the optical...
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KAZUHIRO YAMAMOTO (Faculty of Science, University of Toyama)High PowerPoster
Parametric instability is a serious issue for the stable observation
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operation of current and future gravitational wave detectors.
Although previous studies by K. Yamamoto et al.
(Journal of Physics: Conference Series 122 (2008) 012015)
have suggested that
KAGRA's parametric instability is less serious than
that of LIGO and Virgo, a dedicated mitigation method for KAGRA is... -
Graziano Pascale (Max Planck Institute for Gravitational Physics (Albert Einstein Institute), Hannover)High PowerPoster
The next generation of GW detectors will impose stringent requirements on laser power stability. One promising active power stabilization scheme is based on radiation pressure sensing: laser power fluctuations are transferred into the displacement of a movable mirror (micro-oscillator), which is detected and provides an error signal for the power stabilization control system.
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In 2021, a... -
Andrew Laeuger (Caltech)Quantum NoisePoster
A dielectric particle optically trapped inside a Fabry-Perot cavity has been proposed as a detector for gravitational waves with frequencies from ~10-300 kHz. While standard treatments of levitated optomechanics experiments proceed assuming the levitated particle sources only a perturbative effect on the cavity fields, the atypical properties of the sensors targeted for levitation may break...
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Clément JACQUET (Université de Toulouse, CNRS/IN2P3, L2IT, Toulouse, France)Optical DesignPoster
In order to mitigate thermal noise, the gravitational wave detector KAGRA operates at cryogenic temperatures. Due to its poor thermal and mechanical coefficients, fused silica cannot be used at these temperatures. For this reason, KAGRA’s test masses are made with sapphire.
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Sapphire test masses have inhomogeneous birefringent properties. This property is suspected to distort the error signals... -
Matteo Baratti (Istituto Nazionale di Fisica Nucleare)Thermal noisePoster
Vertical seismic attenuation in gravitational wave detectors relies on materials that show very small creep but their dissipative properties are crucial for assessing the vertical thermal noise that they generate. Due to Earth curvature, vertical thermal noise is projected onto the interferometer plane by a non-negligible vertical-to-horizontal coupling factor, making it a limiting noise...
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Maria Assunto (University of Urbino)Thermal noisePoster
The development of low-noise optical coatings is a crucial challenge for improving the sensitivity of current and next-generation gravitational-wave detectors. A key aspect in optimizing these materials is the identification of the most effective post-deposition heat treatment, as annealing strongly influences both the structural and mechanical properties of the coatings. Among the most...
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Riccardo DesalvoLow Frequency NoisePoster
This report presents a finite element study of the resonance modes of a 2-meter pendulum beam intended for the Einstein Telescope low-frequency cryogenic mirror suspensions. Three beam materials, anisotropic monocrystalline silicon, isotropic monocrystalline sapphire, and isotropic silicon carbide ceramics, were simulated with and without a counterweight. The result shows that the silicon beam...
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Bin Wu (Syracuse University)Thermal noisePoster
Crystalline coatings have been shown to have significantly lower Brownian noise compared to amorphous materials, because oftheir lower mechanical loss. This property offers significant advantages in high-precision metrology and investigations on fundamental physics. In gravitational-wave detection, AlGaAs/GaAs multilayer coatings are considered for next-generation detectors with projected...
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Marco Vardaro (Nikhef/Maastricht University)Low Frequency NoisePoster
The ETpathfinder prototype in Maastricht is dedicated not only to developing and validating key technologies for the Einstein Telescope (ET), but also to testing guidelines and procedures aimed to speeding up and reducing risks in construction of ET.
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The ET will require more than 250 seismic isolation systems. Traditionally, in gravitational-wave observatories, a significant fraction of... -
Margot Hennig (University of Glasgow)Thermal noisePoster
Several polished and super polished fused silica samples were bonded together via optical bonding/direct bond approach and the optical absorption of the bonded area was measured via Photo-thermal common path interferometry (PCI) measurement. The results are presented on this poster.
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Clément JACQUET (Université de Toulouse, CNRS/IN2P3, L2IT, Toulouse, France)Optical DesignPoster
Gravitational wave detectors are complex instruments requiring precise adjustments of their parameters, particularly optical ones, to achieve the highest possible sensitivity. During commissioning, difficulties and problems limiting the sensitivity are identified. Simulations of these detectors play a key role in understanding these phenomena, resolving them, and preparing for future...
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Francisco Salces Carcoba (UNM)Thermal noisePoster
Lenses can't normally achieve part-per-million (ppm) level loss because of coating absorption, surface roughness, diffraction, and other field-related effects. While the first three can be mitigated through annealing, super-polish, and substrate diameter control, thin-film coatings, especially on strongly curved substrates, suffer from a position dependent attenuation or “apodization” effect...
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Léon Vidal (APC)Exploring new directionsPoster
Gravitational waves can excite the Moon’s normal modes, making measurements of lunar deformation a potentially valuable complement to current and future ground- and space-based gravitational-wave observatories. Such deformations may be monitored using inertial sensors, such as seismometers or gravimeters, or through direct strain measurements performed with a laser interferometric instrument...
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Julia RiceOtherPoster
Violin modes in the Advanced LIGO (aLIGO) test mass suspension fibers reduce detector sensitivity at their resonant frequencies and pose operational issues when strongly excited. The violin modes are currently measured at the gravitational wave detector readout and are damped via actuation on the penultimate mass. However, the interferometer must be locked to damp the modes with this method,...
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Yohei Nishino (University of Tokyo)Quantum NoisePoster
This poster summarizes how quantum entanglement and teleportation can be utilized in gravitational-wave detectors. It has two objectives: (1) to improve the quantum-noise-limited sensitivity, reaching and surpassing the standard quantum limit, and (2) to mitigate the technical and economic hurdles associated with various quantum-noise-reduction schemes. Our ideas are potential candidates for...
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James Gardner (University of Chicago)Exploring new directionsPoster
Quantum metrology of an incoherent signal is a canonical sensing problem related to superresolution and noise spectroscopy. We show that quantum computing can accelerate searches for a weak incoherent signal when the signal and noise are not precisely known. In particular, we consider weak Schur sampling, density matrix exponentiation, and quantum signal processing for testing the rank,...
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Tomotada Akutsu (National Astronomical Observatory of Japan)Observatories in spacePoster
Several space missions employ free-falling test masses for high-precision measurements, ranging from gravitational-wave observatories to geophysical sensing. A critical step in such systems is the release of the test mass from the launch-lock mechanism after the spacecraft reaches orbit. Results from the LISA Pathfinder mission showed that the release process can be a high-risk operation,...
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Dr Marc Andrés-Carcasona (MIT)Stray LightPoster
Accurately projecting scattered light noise requires two steps: simulating the steady-state field within long arm cavities and translating these results into strain noise. I will present recent advancements in both directions toward a more robust stray-light modeling framework for 3G observatories. Standard paraxial, free-space FFT propagation tools neglect beam tube boundary effects. By...
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marco nardello (CNRS, OCA Artemis)Stray LightPoster
The performance of the LISA optical bench will be tested in Toulouse by the CNES before flight. The LISA France collaboration is engaged in the design and construction of a test setup to be coupled with the OB (Optical Bench) for that purpose. Among other equipment, the Beams Simulator (BSim) will simulate the telescope and backlink interfaces of the OB, generating a flat top beam and...
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Frederic Cleva (CNRS)Stray LightPoster
We introduce the SLS-Id instrument (Straylight Sources Identifier), designed to measure the amount of light backscattered by any optical components within an integrated optical system. Its application for the Virgo optical benches allows to identify any pathological components, from the straylight perspective, through a system-level measurement. This means that a single measurement will...
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Kenneth Cardona (Louisiana State University)Optical DesignPoster
We use the beam propagation model of the Balanced Homodyne Detection (BHD) readout system currently being installed in LIGO Livingston Observatory for our analysis. In particular, we discuss the new Alignment, Sensing and Control (ASC) of the interferometer with the new wavefront control actuators.
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Joris van Heijningen (VU Amsterdam / Nikhef)Observatories in spacePoster
Gravitational-wave detectors (GWDs) require extremely sensitive and compact sensors to detect and correct for seismic vibration. For future detectors and upgrades of current ones, even the best commercial sensors do not meet the sensitivity requirements. The most critical parts of the Einstein Telescope (ET) will operate at cryogenic temperatures. We could make our current interferometric...
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Nicola Canale (University of Ferrara - INFN Ferrara), Guido Zavattini (Istituto Nazionale di Fisica Nucleare)Optical DesignPoster
The Einstein Telescope will require highly optimized optical substrates to achieve its sensitivity targets. Silicon is one of the primary candidates for cryogenic test masses. We present 2D birefringence maps of silicon samples measured at 1550 nm using a highly sensitive optical polarimeter. Initial measurements of thick substrates ($L \ge 20$ mm) revealed four distinct "poles" of high...
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Michele Vacatello (Istituto Nazionale di Fisica Nucleare)Exploring new directionsPoster
Future third-generation gravitational-wave detectors aim to improve sensitivity by at least an order of magnitude. In this context, enhanced low-frequency performance is crucial for the detection of high-mass and high-redshift systems, improved source localization, timely alerts for electromagnetic follow-up, and the observation of predicted sources such as rotating pulsars. In this...
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Riccardo DesalvoLow Frequency NoisePoster
This study quantifies the cooldown time, post-lock thermal stabilization, and steady-state operating temperature of the Einstein Telescope cryogenic test mass subject to up to 0.5W of mirror heating. The thermal conductance of the small flexures dominates the behavior. Using flexures made of isotopically pure 28Si significantly reduces cooldown time, operating temperature under optical load,...
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Katie Gray (UC Berkeley)Quantum NoisePoster
Quantum noise broadly limits the sensitivity of gravitational-wave detectors like LIGO, with optical losses representing the primary barrier to achieving 10dB of broadband measured squeezing. While O4 demonstrated ~6 dB of measured squeezing at high frequencies using frequency-dependent squeezing via a 300-meter filter cavity [1,2], reaching 10 dB requires loss below 8% - far below the current...
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Dr Georgia Mansell (Syracuse University)Quantum NoisePoster
Quantum noise broadly limits ground-based gravitational-wave detectors. Frequency-dependent squeezing has been implemented at LIGO and Virgo and is used to improve shot noise and radiation pressure noise. Future detectors like Cosmic Explorer require ever greater levels of squeezing enhancement to reach their design sensitivity, though integrating squeezing into these complex high-power...
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Jacques DingQuantum NoisePoster
Continuous-wave interferometers are the sensing backbone of gravitational-wave detectors, but their precision is usually discussed in the regime of standard quantum-limit scaling. In quantum metrology, Heisenberg scaling means that phase-estimation uncertainty improves inversely with the total quantum resource—here, photon flux—rather than with the square root of that resource as in the best...
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Dr Maryrose Barrios (UC Berkeley)Optical DesignPoster
Key hardware improvements such as the upgrade to frequency-dependent squeezing for broadband quantum noise reduction [1] with quantum-limited sensitivities exceeding the Standard Quantum Limit [2] have made LIGO’s 4th observing run (O4) the most successful to-date [3]. Our newest astrophysical catalogue update (GWTC-4 [4]) more than doubles our gravitational-wave event count in about 1/3 of...
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Tobias Schoon (Maastricht university & Nikhef)Optical DesignPoster
The low-frequency interferometer of the proposed Einstein Telescope (ET-LF) will employ cryogenically cooled silicon test masses to reduce thermal noise. Silicon, however, strongly absorbs the currently well-established laser wavelength of 1064 nm, motivating the investigation of alternative wavelengths such as 1550 nm.
This change introduces challenges for interferometer control and lock...
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Craig Cahillane (Syracuse University)High PowerPoster
Photoneutralization technology holds the promise of enabling energy-positive plasma-confinement fusion reactors. Neutral Beam Injection (NBI) is one method of remotely reheating, refueling, and driving the current in a fusion plasma. However, neutralizing a high-amperage ion beam is currently a very inefficient process, topping out at 55% theoretical neutralization efficiency for 1 MeV...
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Dr Johannes EichholzThermal noisePoster
Investigations of thin films produced by pulsed laser deposition (PLD) using ultrafast lasers have previously found low optical loss and good uniformity but were limited by a combination of output power, pulse duration, and single pulse energy of available lasers at the time. These all have steadily increased over the past two decades and allow us to revisit ultrafast PLD (UPLD) today in the...
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Michael PageQuantum NoisePoster
Frequency dependent squeezing can achieve quantum noise reduction across the entire detection bandwidth by rotating the squeezed noise ellipse to match the detector response. However, the rotation must be carefully matched to the main interferometer quantum noise curve, which means that the filter cavity detuning and bandwidth must be carefully set according to the SQL frequency. The high...
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Riccardo DesalvoThermal noisePoster
This presentation describes the impact on the sensitivity of the ET low-frequency detector that the vertical thermal noise of the room-temperature seismic isolation system produces. It is shown that longer arms and more tilted tunnels produce larger contributions along the interferometer arm, which in any configuration is larger than the ET desired sensitivity. A method that has been proposed...
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