Probing material absorption and optical nonlinearity of integrated photonic materials.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 35680923.
- Also identified by DOI 10.1038/s41467-022-30966-5 and PMC identifier 9184588.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
Optical microresonators with high quality (Q) factors are essential to a wide range of integrated photonic devices. Steady efforts have been directed towards increasing microresonator Q factors across a variety of platforms. With success in reducing microfabrication process-related optical loss as a limitation of Q, the ultimate attainable Q, as determined solely by the constituent microresonator material absorption, has come into focus. Here, we report measurements of the material-limited Q factors in several photonic material platforms. High-Q microresonators are fabricated from thin films of SiO<sub>2</sub>, Si<sub>3</sub>N<sub>4</sub>, Al<sub>0.2</sub>Ga<sub>0.8</sub>As, and Ta<sub>2</sub>O<sub>5</sub>. By using cavity-enhanced photothermal spectroscopy, the material-limited Q is determined. The method simultaneously measures the Kerr nonlinearity in each material and reveals how material nonlinearity and ultimate Q vary in a complementary fashion across photonic materials. Besides guiding microresonator design and material development in four material platforms, the results help establish performance limits in future photonic integrated systems.