Diophantine optics in nulling interferometry: laboratory performances of the chessboard phase shifter
Abstract
Among the techniques of very high angular resolution to isolate planetary photons from those of the star - several million times more numerous - a possible one is the nulling interferometry with several telescopes in space. This mode requires an achromatic phase shift of pi in one arm of the interferometer. We introduced several years ago the concept of quasi-achromatic phase shifter based on two chessboard mirrors, each cell introducing a phase shift determined by a mathematical law, so that the behavior of the attenuation of the star as a function of wavelength is flat in a range of more than one octave. This concept is part of broader field that we call "diophantine optics" and that will be first presented. We then present the experimental validation of such a concept where the chessboard phaser is synthesized using a properly controlled deformable segmented mirror from Boston micro machine with 12x12 actuators. First we introduce the principle of the "chessboard effect", then the dedicated testbench DAMNED will be described in particular the control of the phase through strioscopy. The results on the performances of the device will be presented and the ways of improvement and extension of this concept will be analyzed.
- Publication:
-
Improving the Performances of Current Optical Interferometers & Future Designs
- Pub Date:
- April 2014
- Bibcode:
- 2014ipco.conf..197R
- Keywords:
-
- optical interferometry;
- delay-lines;
- sparse apertures;
- beam combiners;
- fringe tracking;
- laser telemetry;
- heterodyne interferometry;
- image reconstruction;
- nulling interferometry