5. Laboratory Demonstration

Team

Mark Ammons (UofA)      Lab demo design & operation
Eduardo Bendek (UofA)   Lab demo optical design & operation
Olivier Guyon (UofA)    Lab demo design, data analysis
Tom Milster (UofA)      Mask manufacturing, scaling of mask manufacturing to full scale PM
Jim Burge (UofA)	Mask manufacturing, scaling of mask manufacturing to full scale PM

5.1 Overview

A laboratory demonstration of the concept is currently under assembly at the University of Arizona. Results will be posted here as they become available. The goal of the lab demo is to validate the concept, verify the error budget, identify outstanding issues and test/develop data analysis algorithms.

We also plan to verify that the PM dots are compatible with high contrast coronagraphy by inserting dotted masks in existing coronagraph testbed(s).

5.2 Mask manufacturing

The first mask prototype has been manufactured. As shown in Figure 5-1, the far-field pattern consists of a bright central spot (the main lobe of the PSF) surrounded by a grid of diffraction spots. In broadband light, these spots are spectrally dispersed in long spikes.

Figure 5-1: First mask prototype [png]
Images taken by Eduardo Bendek

Figure 5-2: White light diffraction pattern obtained by reflection on the dotted prototype mirror [png]
Image taken by Eduardo Bendek

5.3 Lab experiment design

In our lab experiment, the dotted mirror is a flat, and is the first optical element after the light source. An OAP relay is used to focus the image on a CCD. The source scene, which includes a bright central star and a set of fainter background stars, can be rotated to simulate a telescope roll. The OAPs are full parabolas, of which only a portion is used.