Abstract
We present a modified commercial L-4C geophone with interferometric readout that demonstrates a resolution 60 times lower than the included coil-magnet readout at low frequencies. The ...intended application for the modified sensor is in vibration isolation platforms that require improved performance at frequencies lower than 1 Hz. To illustrate it’s application a controls- and noise-model of an Advanced LIGO ‘HAM-ISI’ vibration isolation system was developed, and shows that our sensor can reduce the residual motion of the platforms by a factor of 70 at 0.1 Hz.
Abstract Laser frequency stabilization is a crucial technique for precision metrology. We demonstrate laser frequency control using a compact, interferometric sensor, specially modified for ...sensitivity to laser frequency noise. This setup achieves a balance between compact size, ease of use, and affordability. We stabilize the laser frequency noise, of a low-cost solid-state laser, to 4.5 k H z H z − 1 at 1 Hz. The requirement for additional technology, and expense, is negated when identical, compact, interferometric sensors are deployed. The use of compact interferometric sensors is already a technology under investigation for integration into gravitational-wave observatories and out study enables wider applications by mitigating a fundamental noise source, inherent to their design.
The successful detection of gravitational waves from astrophysical sources carried out by the laser interferometric detectors LIGO and Virgo have stimulated scientists to develop a new generation of ...more sensitive gravitational wave detectors. In the proposed upgrade called LIGO Voyager, silicon test masses will be cooled to cryogenic temperatures. To provide heat removal from the test masses when they absorb the laser light one can increase their thermal emissivity using a special black coating. We have studied mechanical losses in a carbon nanotube black coating deposited on silicon wafers. The additional thermal noise associated with mechanical loss in this coating was calculated using a value of the product of the coating Young's modulus and the coating mechanical loss angle determined from the measurements. It was found that at temperatures of about 123 K, the additional thermal noise of the LIGO Voyager test mass caused by the carbon nanotube black coating deposited on its barrel is less than the noise associated with the Acktar Black coating and is 20 times less than the noise due to the optical high reflective (HR) coating of the test mass.
Investigation of mechanical dissipation in silicon ribbons is important for the development of low noise silicon test mass suspension of the future interferometric gravitational wave detectors. ...Ribbon-like oscillators were fabricated in commercial silicon wafers using the anisotropic chemical wet etching technique. Results of measurement of the mechanical loss of such oscillators in the temperature range from 90 K to 300 K are presented. Suppression of thermoelastic loss down to at the temperature of about 124 K is observed.
The cooling of devices fabricated from single-crystal silicon to a temperature of 123 K at which its coefficient of thermal expansion passes through zero makes it possible to improve their stability ...and reduce noise. In the temperature range of 100–295 K, the temperature dependences of losses (attenuation) and changes in the resonance frequency of a tuning-fork mechanical resonator fabricated from silicon strips and joined by direct bonding are investigated. It allows the quality of the join to be controlled in a non-destructive way as well as to identify the features of the behavior and changes, which occur at the interface with time.
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DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NLZOH, NUK, OBVAL, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, SIK, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Some proposed interferometric gravitational wave detectors of the next generation are designed to use silicon test masses cooled to cryogenic temperatures. The test masses will need to be partially ...coated with high emissivity coating to provide sufficient cooling when they absorb the laser light. The mechanical loss of the Acktar Black coating is determined based on the measurements of the Q-factors of the bending vibration modes of coated and uncoated commercial silicon wafers. The Young's modulus of the coating material is determined using nanoindentation. We use this information to calculate thermal noise of the silicon test masses associated with a high emissivity coating on its lateral side (barrel). It is found that such a coating results in a less than 9% increase of the total strain noise of LIGO Voyager design for a future cryogenic gravitational wave detector.
On 14 September 2015, the two detectors of the Laser Interferometer Gravitational-wave Observatory (LIGO) in the US recorded the first direct detection of gravitational waves. This paper reviews the ...contributions to this discovery by V B Braginsky's group at the Physics Department of Lomonosov Moscow State University.
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