  Sapphire is a promising wideband substrate material for visible photonics. It
is a common growth substrate for III-nitride light-emitting diodes and laser
structures. Doped sapphires are important gain media foundational to the
development of titanium-sapphire and ruby lasers. For lasers operating at
visible and near-infrared wavelengths, a photonic platform that minimizes loss
while maximizing gain material overlap is crucial. Here, we introduce a novel
low-loss waveguiding strategy that establishes high-performance integrated
photonics on sapphire substrates. This platform achieves a high intrinsic
quality factor of 5.6 million near 780 nm and features direct compatibility
with a range of solid-state laser gain media.
