On the detectability of the Lense–Thirring field from rotating laboratory masses using ring laser gyroscope interferometers

Abstract

The possibility of detecting the Lense–Thirring field generated by the rotating earth (also rotating laboratory masses) is reassessed in view of recent dramatic advances in the technology of ring laser gyroscopes. This possibility is very much less remote than it was a decade ago. The effect may contribute significantly to the Sagnac frequency of planned instruments. Its discrimination and detection will require an improved metrology, linking the ring to the celestial reference frame, and a fuller study of dispersion- and backscatter-induced frequency pulling. Both these requirements have been the subject of recent major progress, and our goal looks feasible.

A 1.82 m2 ring laser gyroscope for nano-rotational motion sensing

“…"G", together with other large gyrolasers around the world (for a detailed list of references see for example http://www.ringlaser.org.nz), provides essential information on rotational seismology [2] and its long-term monitoring of the earth rotation rate makes the direct observation of geodetic effects like the solid earth tides [3] and the diurnal polar motion [4] possible. The present sensitivity level is not too far from what is required for ground based General Relativity tests, which seem achievable in the near future by improved devices [5,6,7]. In this paper we present the experimental results concerning the use of a meter size gyrolaser as very sensitive tilt sensor.…”

Gravitomagnetic field of rotating rings

“…A nonstandard form of gravitomagnetism has been recently analyzed by Acedo (2014a,b), in a purely phenomenological context. Eventually, the possibility of testing GM effects in a terrestrial laboratory has been considered by many authors in the past (Braginsky et al 1977(Braginsky et al , 1984Cerdonio et al 1988;Ljubičić and Logan 1992;Camacho 2001;Iorio 2003;Pascual-Sánchez 2003;Stedman et al 2003;Iorio 2006b); a recent proposal pertains to the use of an array of ring lasers (Bosi et al 2011;, and is now underway (Di Virgilio et al 2014).…”

On the potential of large ring lasers

“…However, in the years after Anandan & Chaio's paper [1] and before Josephson effects were realised in super-fluid junctions, a revolution in mirror design has meant that reflectivities rose until they are now > 99.999% so that cavity quality factors and finesses have risen to values of 2•10 13 and 10 5 respectively [3] [4]. Since [4] our team now has constructed a rectangular laser gyroscope UG2 of 21m X 39.7m with area A = 833.7m 2 and perimeter P = 121.4 m as an upgrade since November 2005 of an earlier and smaller laser, UG1. In addition a new generation of super-mirrors has been installed in this machine, also in an earlier machine C-II.…”

“…In addition a new generation of super-mirrors has been installed in this machine, also in an earlier machine C-II. It is therefore time to update Table 1 of an earlier study [4] and this is done in the present paper. We also report new results for beam powers, sizes, and ring-down times and their consequences for possible sensitivity.…”

“…However we have to note, that a much more elaborate mechanical sensor design is required to fully utilize the potential of these larger rings. The currently explored structures cannot make full use of their enhanced sensor resolution.Two proposals have been suggested for still larger such machines [4]. One ring laser, UG100, would be 100 m square with a radical different cavity design and the other MCR for Michelson Centennial Ring is proposed to update the classic work of Michelson, Gale and Pearson in 1925 [21] to the laser era.…”