Ultrahigh-resolution thermometry is critical for future advances in bio-calorimetry^1,2, sensitive bolometry for sensing³ and imaging⁴, as well as for probing dissipation in a range of electronic⁵, optoelectronic⁶ and quantum devices⁷. In spite of recent advances in the field^8,9,10,11, achieving high-resolution measurements from microscale devices at room temperature remains an outstanding challenge. Here, we present a band-edge microthermometer that achieves this goal by relying on the strong, temperature-dependent optical properties of GaAs at its absorption edge^12,13,14. Specifically, using a suspended asymmetric Fabry–Pérot resonator and a wavelength-stabilized probe laser we demonstrate a thermoreflectance coefficient of >30 K⁻¹, enabling measurements with a thermometry noise floor of ~60 nK Hz^−1/2 and a temperature resolution of <100 nK in a bandwidth of 0.1 Hz. The advances presented here are expected to enable a broad range of studies and applications in calorimetry and bolometry where miniaturized high-resolution thermometers are required.

超高分辨率测温对于生物量热法^1,2、用于传感³和成像⁴的敏感辐射热测量法以及探测电子⁵、光电⁶和量子器件⁷范围内的耗散的未来进展至关重要。尽管该领域^{8、9、10、11}取得了最新进展，但在室温下从微型设备实现高分辨率测量仍然是一项突出的挑战。在这里，我们展示了一种带边测温仪，它依靠 GaAs 在其吸收边缘^{12、13、14的强、与温度相关的光学特性来实现这一目标}. 具体来说，使用悬浮的非对称法布里-珀罗谐振器和波长稳定的探针激光器，我们展示了 >30 K ^{-1的热反射系数，能够以~60 nK Hz -1/2}的温度测量噪声基底和温度分辨率进行测量<100 nK，带宽为 0.1 Hz。这里介绍的进展有望在需要微型高分辨率温度计的量热法和辐射热测量法中进行广泛的研究和应用。