Monolithic Optical Components for Astronomical
Spectrographs
Abstract
Earth-bound extremely large telescopes will require efficient transmissive and diffractive optical components to conduct spectral astronomical surveys. Currently used high-resolution spectrograph gratings have diffraction efficiency limitations, and antireflective thin film coatings have non-uniform broadband spectral signatures. This presentation reports results to improve astronomical instrumentation light-throughput efficiency by fabricating monolithic binary-phase gratings in quartz substrates, and by nano-texturing the surfaces of various optical elements to enhance their transmission. The performance of the fabricated devices are directly compared with commercially available components. The spectrograph gratings have 35-50% higher diffraction efficiency compared to volume phase holographic gratings, and the nanotextured components have broadband transmission efficiency greater than 98%, without interference oscillations or scatter. The transmission enhanced optics were tested as part of a light relay system, alongside conventional components, and showed better system performance as well.
Short Biography
Menelaos K. Poutous is an Associate Professor with the Department of Physics & Optical Science at the University of North Carolina – Charlotte, USA. He previously held a Principal Development Engineer’s position at Digital Optics Corporation, and before that, he was Lecturer with the Department of Physics at Emory University. He received his Doctorate from the School of Physics at the Georgia Institute of Technology, Atlanta GA. He leads experimental research in micro- and nano-structured optical surfaces, with a number of collaborative projects funded by US National Laboratories, private industry partners, and research foundations. He is currently investigating fabrication of spectroscopic gratings and optical antireflective surfaces for future applications in Extremely Large Telescopes. His research interests are in spectroscopy, diffractive micro-optical elements, photolithographic fabrication processes, micro-optics in laser cavities and artificial optical surfaces. He is a senior member and course instructor of the International Society for Optics and Photonics (SPIE).
