Alexander Hedglen

PhD Student

High Contrast Adaptive Optics Co-Phasing

Adaptive Optics -- High Contrast Imaging -- Interferometry -- Optical Design -- Wavefront Sensing

Current Research Summary:

The GMT design consists of seven circular 8.4-m diameter segments separated by 30-40 cm gaps, creating the possibility of fluctuations in optical path differences between each mirror segment due to flexure, wind loading, and temperature effects. In order to utilize the full diffraction-limited aperture of the GMT, the seven mirror segments must be co-phased to within a fraction of a wavelength. I’m working on the design and build of a “GMT High-Contrast Phasing Testbed” which leverages the existing MagAO-X ExAO instrument to demonstrate fine phase sensing and simultaneous AO-control for high-contrast GMT natural guide star science. The testbed will simulate the GMT primary and secondary mirror phasing system and will include a GMT dispersed fringe sensor and a pyramid wavefront sensor to measure and correct the phasing of the GMT under realistic wind load and seeing conditions.

Prior Research: