Speaker
Description
Within the Italian PNRR project ETIC, the ADONI-ET Optical Laboratory, managed by INAF, developed an interferometric testbed to investigate adaptive optics (AO) applications to Thermal Compensation Systems (TCS), with the aim of developing closed-loop control strategies for gravitational-wave detectors.
In this work, we used a deformable mirror (DM) to thermally induce wavefront aberrations in an interferometric laboratory setup. A 1~W, 1064 nm collimated laser beam was shaped by an Alpao DM and absorbed by a Schott KG5 glass test piece (GTP). The GTP transmitted wavefront was measured in real time, as optical path difference (OPD) with respect to a reference configuration (flat DM) using an interferometer. This approach is analogous to control strategies used in astronomical AO systems.
We characterized the system response by measuring the thermal influence functions linking the DM commands to the induced OPD signals, and constructed the corresponding interaction matrix. This allowed us to describe the system in the linear regime and to test its control via matrix inversion.
We generated a basis of up to 33 OPD modes on the test piece, demonstrating a high degree of control over the induced thermal aberrations, and analyzed their amplitude and linearity with respect to the applied DM commands.
These results constitute an experimental demonstration of deformable-mirror-driven thermal mode generation, and represent a step toward closed-loop thermal correction schemes.