An optical read-out system for the LISA gravitational reference sensor: present status and perspectives

Since a few years, the LISA-PF group in Napoli has been working to the development of an optical read-out system, based on optical levers and position sensitive detectors, for the LISA Gravitational Reference Sensor (GRS). This is intended as a more sensitive extra sensing device, in addition to capacitive readout that is the reference solution already tested on flight by the LISA-Pathfinder mission. The reliability of the proposed ORO device and the fulfillment of the sensitivity goals have been already demonstrated in bench-top measurements and tested with torsion pendulum facilities. In this paper we report on the present status of this activity, presenting the results obtained so-far and the perspectives for the future LISA mission.