This project will develop novel filters called ring-resonators, imprinted on silicon wafers, to suppress the atmospheric airglow at near-infrared (NIR) wavelengths where cool stars, proto-planets and galaxies glow most brightly. The airglow, coming from narrow emission-lines produced by OH molecules in the upper atmosphere, prevent astronomers from taking full advantage of this window from ground-based observatories. The ring resonators create narrow-band notch filters (like an uneven picket fence with very narrow pickets), thermally tuned to block the air-glow lines but let most of the light from astronomical objects through. This program focuses on solving the engineering problems associated with coupling light from telescopes efficiently into the ring-resonators, and then back out to feed conventional instruments, such as spectrographs. By the conclusion of this project, leveraged by US industrial partners, the technology will be sufficiently advanced for on-sky demonstration of ring resonator-based air-glow suppression. Working with Lowell Observatory’s Marley Foundation Astronomy Discovery Center, this program also will develop a portable, interactive exhibit focused on the critical thinking and the problem-solving tools used by scientists and engineers in the development of astronomical instrumentation. Ring resonator filters currently offer the only viable alternative (potentially in a more compact package) to fiber Bragg gratings (not fabricated in the US) for redu