I work on breaking down the barriers to imaging at the very highest angular resolutions in astronomy. I use interferometric arrays of telescopes to yield images with an angular resolution more than one hundred times better than that of the Hubble Space Telescope.
Interferometry is subject to fundamental limitations due to the paucity of photons from astronomical sources and the perturbations to the optical phase introduced by the Earth's atmosphere. My research uses a wide range of techniques to overcome these limitations and thereby probe astrophysical processes on scales which cannot be accessed by any other means.
Fundamentals of interferometry
My scientific contributions include a number of significant firsts:
- making the first image of surface features on any star apart from the Sun (Buscher 1990);
- developing the first image reconstruction software to adapt radio interferometric technologies to the noise model of optical measurements (Buscher 1993), a model now adopted by all image reconstruction packages in this field;
- making the first direct measurements of the outer scale of the optical turbulence which limits the performance of imaging systems (Buscher 1995).
Much of my research over the last decade has been dedicated to the design and construction of the Magdalena Ridge Observatory Interferometer (MROI), a project to build the world's most ambitious optical array. MROI will be able to image targets 10 times fainter than those accessible with any other interferometer, and it will be able to make images on timescales of hours instead of days (Buscher et al 2013).
I have established a new Precision Instrumentation activity in Cambridge which develops:
- photon-counting near-infrared detectors (Buscher et al 2016)
- metre-sized diffraction gratings which are stable at parts in a billion.
- readout schemes for high-precision near-infrared spectrographs
- developing modal noise suppression systems for ultra-stable spectrographs.