Phys.org   September 26, 2023 UV and visible photonics enable applications ranging from spectroscopic sensing to communication and quantum information processing. Photonics structures in these wavelength regimes tend to experience higher loss than their IR counterpart. Particularly in the near-UV band, on-chip optical microresonators have not yet achieved a quality factor beyond 1 million. A team of researchers in the US (Yale University, industry) developed ultra-low-loss photonic waveguides and resonators patterned from alumina thin films prepared by a highly scalable atomic layer deposition process. They demonstrated ultra-high Q factor of 1.5×106 at 390 nm, a record value at UV bands, and 1.9×106 […]