Early technology developments for gravitational-wave instrumentation and wider applications

Lead Research Organisation: University of Glasgow
Department Name: School of Physics and Astronomy

Abstract

This equipment proposal is designed to enhance and maintain Glasgow and the UK's ability to stay at the forefront of the R&D of early technology critical in delivering future science goals, both for the core gravitational waves program and wider applications, at a time when the field is in a period of rapid growth.

Much of the experimental work funded by our consolidated grant is in the areas of developing suspensions and in designing and measuring improved mirror coatings for the next stages of current detectors as well as for the next generation. We believe that our international competitiveness and overall impact in the field will be significantly enhanced by the purchase and development of state of the art material preparation, fabrication and diagnostic equipment to enhance our development of key technologies.

Thus for our suspensions research we are requesting funding for a carbon dioxide laser, providing enhanced capabilities for the precision welding of silica and sapphire fibres to attachments bonded to the sides of test masses. This is an essential technique for the construction of mirror suspension assemblies in gravitational wave detectors, and has wider applications including the construction of components of portable atomic clocks.

For our research into mirror coatings and substrates, we are requesting funding for a cryogen-free cryostat for cryogenic studies of the key properties of optical absorption and mechanical loss. Mirror coatings with low optical absorption and low mechanical loss have wider applications in the fields of quantum technology and atomic clocks. This cryostat will also enable studies of the cryogenic mechanical loss of our crystalline suspension fibres being developed for ultra-low noise performance in future gravitational wave detectors. These studies will include tests of laser-welded components fabricated with the CO2 laser requested on this grant. Finally, the cryostat will support our research into precision bonding techniques for use in the construction of the suspended mirrors used in gravitational wave detectors.

To support the development and testing of new experimental systems, we request a MOKU Professional multi-instrument system. This system comprises a data logger, arbitrary and specific waveform generators, PID controller, lock-in amplifier, phase meter, spectrum analyser, digital filter algorithms and a dedicated system for laser stabilisation, all controllable through a computer interface. This will provide a highly portable system for diagnostic testing and developing experimental setups, with particular relevance for the development of our cryogenic prototype interferometer system and for the development of actuation and sensing systems for measuring the mechanical loss of mirror coatings and suspension fibres.

The basic R&D in sensors for precision measurement enabled using these equipment items has wide-ranging applications in related fields including in applied optics (where our novel research on oxide bonding has enabled advances in high-power solid-state laser performance), and in coatings (where developments driven by the GW field are being adopted to created optical clocks of improved performance).

We should note that none of our proposed purchases raises any issues with respect to the UKRI Framework for Responsible Innovation.

Publications

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