Angela Di Virgilio

Compensation of the laser parameters fluctuations in large ring laser gyros: a Kalman filter approach

He-Ne ring-laser gyroscopes are, at present, the most precise devices for absolute angular velocity measurements. Limitations to their performance come from the nonlinear dynamics of the laser. Following Lamb semiclassical theory, we find a set of critical parameters affecting the time stability of the system. We propose a method for estimating the long-term drift of the laser parameters and for filtering out the laser dynamics effects from the rotation measurement. The parameter estimation procedure, based on the perturbative solutions of the laser dynamics, allows us to apply Kalman filter theory for the estimation of the angular velocity. Results of a comprehensive Monte Carlo simulation and results of a preliminary analysis on experimental data from the ring-laser prototype G-Pisa are shown and discussed.

Prospects for stochastic background searches using Virgo and LSC interferometers

We consider the question of cross-correlation measurements using Virgo and the LSC Interferometers (LIGO Livingston, LIGO Hanford and GEO600) to search for a stochastic gravitational-wave background. We find that inclusion of Virgo into the network will substantially improve the sensitivity to correlations above 200 Hz if all detectors are operating at their design sensitivity. This is illustrated using a simulated isotropic stochastic background signal, generated with an astrophysically-motivated spectral shape, injected into 24 h of simulated noise for the LIGO and Virgo interferometers.

Deep underground rotation measurements: GINGERino ring laser gyroscope in Gran Sasso

GINGERino is a large frame laser gyroscope investigating the ground motion in the most inner part of the underground international laboratory of the Gran Sasso, in central Italy. It consists of a square ring laser with a 3.6 m side. Several days of continuous measurements have been collected, with the apparatus running unattended. The power spectral density in the seismic bandwidth is at the level of 10-10 (rad/s)/Hz. A maximum resolution of 30 prad/s is obtained with an integration time of few hundred seconds. The ring laser routinely detects seismic rotations induced by both regional earthquakes and teleseisms. A broadband seismic station is installed on the same structure of the gyroscope. First analysis of the correlation between the rotational and the translational signal is presented.Large ring-laser gyroscopes are capable of measuring angular rotations with a precision well below fractions of

Testing general relativity by means of ring lasers

prad/s

Laser gyroscopes for very high sensitive applications

, not far from

Planar angle metrology: G-LAS, the INRIM - INFN ring laser goniometer

10^{-14}

G-LAS a ring laser goniometer for angular metrology

rad/s

The GINGER Project and status of the ring-laser of LNGS

, the accuracy required for General Relativity tests, this is what the GINGER (Gyroscope-IN-GEneral-Relativity) experiment is aiming for. These features do not guarantee the possibility of measuring the General Relativity Lense--Thirring effect, that manifests itself as a tiny (

A network of heterodyne laser interferometers for monitoring and control of large ring-lasers

\approx 10^{-9} \times \Omega_E