Ultraprecision photonic thermometry with nonadiabatically modulated coupled resonances

Abstract

Sensing minute temperature fluctuations is of key importance to many cutting-edge industrial and scientific applications. While recent developments in microphotonic thermometers have achieved unmatched sensitivity, the wide adoption of these sensors is hindered by their limited dynamic range as well as the complex design. Here, we present a coupled-resonance-based scheme that utilizes a single-laser-driven optical microresonator to enable self-referenced thermometry with unprecedented simplicity. The thermometry complexity is further reduced by applying nonadiabatic modulation to the coupled resonances, which not only eliminates the need for external modulation but also yields a record-setting few-nanokelvin resolution. To highlight the applicability and the versatility of the developed thermometers, state-of-the-art microresonator applications including laser frequency stabilization and robust nonlinear frequency conversion are demonstrated over a wide range of operating temperatures. Being compatible with existing photonic integrated circuit building blocks, this easy-to-use, high-performance thermometry approach may be implemented extensively in compact optical and photonic systems.