High Resolution Measurement of Near-Field Radiative Heat Transfer enabled by Nanomechanical Resonators

TL;DR

This paper demonstrates high-resolution near-field radiative heat transfer measurements using silicon nitride nanomembranes, achieving unprecedented temperature resolution and aligning well with theoretical models.

Contribution

It introduces a novel experimental platform with nanomembranes for NFHT measurement, enabling high precision and material versatility.

Findings

Achieved temperature resolution of 1.2×10⁻⁶ K.

Measured NFHT using high-Q nanomembranes.

Results agree with a custom heat transfer model.

Abstract

Near-field radiative heat transfer (NFHT) research currently suffers from an imbalance between numerous theoretical studies, as opposed to experimental reports that remain, in proportion, relatively scarce. Existing experimental platforms all rely on unique custom-built devices on which it is difficult to integrate new materials and structures for studying the breadth of theoretically proposed phenomena. Here we show high-resolution NFHT measurements using, as our sensing element, silicon nitride (SiN) freestanding nanomembranes$-$a widely available platform routinely used in materials and cavity optomechanics research. We measure NFHT by tracking the high mechanical quality (Q) factor ($>2\times10^6$) resonance of a membrane placed in the near-field of a hemispherical hot object. We find that high Q-factor enables a temperature resolution ($1.2\times10^{-6} \ \mathrm{K}$) that is unparalleled in previous NFHT experiments. Results are in good agreement with a custom-built model combining heat transport in nanomembranes and the effect of non-uniform stress/temperature on the resonator eigenmodes.