Quantum noise limits the performance of gravitational-wave (GW) detectors, optomechanical experiments, and even recently proposed dark matter searches. This talk discusses the effort of the Birmingham group towards studies of the quantum noise in these experiments. In particular, we will show how to employ the couple cavity resonance for high GW frequency detectors, heterodyne squeezing...
Cavity optomechanics can be used to improve the sensitivity of gravitational-wave detectors via optomechanical filtering and ponderomotive squeezing. Here we present a concept for double resonant enhancement of optomechanical interaction in a multi-cavity optomechanical system that exhibits resonance splitting tuned to be equal to the mechanical resonant frequency. In a detuned cavity in the...
The decades of advancement in technologies pertaining to interferometric measurements have made it possible for us to make the first-ever direct observation of gravitational waves(GWs). These GWs emitted from violent events in the distant universe bring us crucial information about the nature of matter and gravity. In order for us to be able to detect GWs from even farther or weaker sources,...
Squeezed light has been employed at GEO 600 for almost 10 years, recently reaching the highest level ever measured on a large scale interferometer. This improvement was achieved after work towards the reduction of optical losses in the squeezed light injection path.
The in-air injection path was rebuilt by cleaning and substituting some optics. Faraday isolators were carefully tuned in order...
Squeezed light now has a firm place as a key technology for reducing the quantum noise in gravitational-wave detectors. Quantum noise of coherent and squeezed states is characterized by gaussian measurement uncertainties in their amplitude and phase quadratures. While in a coherent state both quadratures have the same (minimal) uncertainty, in squeezed states the uncertainty in one quadrature...
Vacuum fluctuations entering the dark port of an interferometric Gravitational Wave (GW) detector are responsible for Quantum Noise (QN).
The high-frequency component of QN is Shot Noise (SHN), while the low-frequency one is Radiation Pressure Noise (RPN).
The sensitivity of the present detectors is only affected by the first, being the RPN covered by techinical noises. SHN reduction,...
In 2015, after many years of R&D efforts of the LIGO-Virgo collaboration for the upgrade to the second generation of ground based gravitational wave detectors, for the first time it has been possible a direct observation of a gravitational wave event (GW). In the following years, many other GW events have been detected by both LIGO and Virgo. Nevertheless, in the very near future the present...
