Measuring the Orbital Angular Momentum of Light for Astronomy

While the story of optical orbital angular momentum (OAM) dates back to the development of Maxwell's equations, the study of photon OAM by the physics community begins in earnest in the 1990s, led in part by a paper by Allen et al. describing the independent control of spin and orbital angular momentum in paraxial modes of light. The recognition of the orbital angular momentum of light in astronomy is a much more recent affair. This thesis explores the role of the OAM of light in astronomy and attempts to make the case for the measurement of photon OAM as a new tool in astronomy. Two contributions are made in order to prepare the groundwork for future endeavours: a laboratory assessment of the effectiveness of adaptive optics (AO) systems on atmospheric turbulence when measuring optical OAM, and an initial field test of an instrument measuring the optical OAM spectrum of the sun. Regarding the first study, the author finds that realistic atmospheric turbulence (1'' seeing) severely corrupts any incoming OAM signal at visible wavelengths, in spite of AO correction (