Current results of the PERSEE testbench: the cophasing control and the polychromatic null rate

TL;DR

The paper reports on the PERSEE testbench's progress in achieving nanometric stabilization of a nulling interferometer, demonstrating precise control and deep null depths in a space-like environment.

Contribution

This work presents the current results of the PERSEE testbench, including advanced control techniques and null depth achievements in a realistic disturbance environment.

Findings

Achieved 0.33 nm rms piston control

Maintained null depth of 8.9E-6 over 37% bandwidth

Demonstrated effective vibration control with LQG

Abstract

Stabilizing a nulling interferometer at a nanometric level is the key issue to obtain deep null depths. The PERSEE breadboard has been designed to study and optimize the operation of a cophased nulling bench in the most realistic disturbing environment of a space mission. This presentation focuses on the current results of the PERSEE bench. In terms of metrology, we cophased at 0.33 nm rms for the piston and 80 mas rms for the tip/tilt (0.14% of the Airy disk). A Linear Quadratic Gaussian (LQG) control coupled with an unsupervised vibration identification allows us to maintain that level of correction, even with characteristic vibrations of nulling interferometry space missions. These performances, with an accurate design and alignment of the bench, currently lead to a polychromatic unpolarised null depth of 8.9E-6 stabilized at 3E-7 on the [1.65-2.45] \mum spectral band (37% bandwidth).