Photothermal Microscopy & Spectroscopy with Nanomechanical Resonators

TL;DR

This paper introduces nanomechanical resonators as highly sensitive, self-measuring tools for photothermal spectroscopy and microscopy, enabling detection of trace analytes and single molecules through thermal resonance shifts.

Contribution

The work presents a novel approach using nanomechanical resonators as integrated, self-measuring spectrometers capable of detecting heat transfer from substances across a broad spectrum.

Findings

Resonators can detect trace analytes and single molecules.

High sensitivity achieved despite thermal fluctuation limits.

Versatile design supports various sampling and spectroscopic methods.

Abstract

In nanomechanical photothermal absorption spectroscopy and microscopy, the measured substance becomes a part of the detection system itself, inducing a nanomechanical resonance frequency shift upon thermal relaxation. Suspended, nanometer-thin ceramic or 2D material resonators are innately highly-sensitive thermal detectors of localized heat exchanges from substances on their surface or integrated into the resonator itself. Consequently, the combined nanoresonator-analyte system is a self-measuring spectrometer and microscope: responding to a substances transfer of heat over the entire spectrum for which it absorbs, according to the intensity it experiences. Limited by their own thermostatistical fluctuation phenomena, nanoresonators have demonstrated sufficient sensitivity for measuring trace analyte as well as single particles and molecules with incoherent light or focused and unfocused coherent light. They are versatile in their design, support various sampling methods and hyphenation with other spectroscopic methods, and are capable in a wide range of applications including fingerprinting, separation science, and surface sciences.