Paper 13100-65
Paper 13100-65
Magnetorheological Finishing of Volume Phase Holographic Gratings for High Fidelity Spectrograph Wavefront Performance
19 June 2024 • 10:30 - 10:45 Japan Standard Time | Room G214, North - 2F
Abstract
Volume phase holographic gratings (VPHGs) manufactured with dichromated gelatin (DCG) have become a staple of astronomical spectrograph design due to their high first order diffraction efficiency, low stray light, and high index modulation, which enables wide spectral bandwidths and angular tuning. In this talk, we will look at one optical limitation of VPHGs – wavefront error – and how custom magnetorheological finishing (MRF) can be used to mitigate it. We will demonstrate the improvement achieved with MRF using an exploratory grating fabricated for the future HARMONI Spectrograph to be deployed at ESO’s Extremely Large Telescope (ELT).
Presenter
Wasatch Photonics, Inc. (United States)
Elroy Pearson holds the role of Senior Optical Engineer at Wasatch Photonics, to which he brings deep holographic experience as well as multi-disciplinary breadth. Elroy studied computer engineering initially, going on to pursue an MSc at MIT with a thesis in holographic displays. Early in his career, he apprenticed with the founder of Wasatch Photonics, during which time he helped develop the world class gratings for which the company is known. Since 1996, Elroy has led and contributed to optical design teams working on holographic technologies and tools ranging from large-aperture, multiplexed holographic optics for lidar to holographic data storage as well as holographic printers and holographic video displays. He also spent a decade of his career creating automated and microfabricated tools for pharmaceutical research, optical zoom camera modules for consumer electronics, giving him a unique perspective and insight into the applications of holographic optical elements.