Measuring temperature produced by plasmonic metal nanoparticles using wavefront microscopy

In fifteen words or less, explain the significance of this contribution (Novel Aspect).: This work is significant because it addresses misconceptions in understanding temperature gradients produced by nanoheaters.

Abstract Text:

Predicting the temperature of nanoparticles and their environment in plasmonically-driven processes is critical for advancing progress in applications including chemical conversion and sensing. Although heat diffusion models can provide accurate temperature predictions in simple systems, a direct experimental approach is necessary as experiments become more advanced. This is particularly true when many nanoparticles are illuminated at once and collective heating effects dominate. A variety of micro-nano thermometers exist already that measure temperature either through contact-based thermocouple-inspired techniques, luminescent nanoparticle-based imaging or spectroscopy techniques, and light-based interferometry techniques. In this talk, I will discuss how I use one emergent interferometry thermometer, Quadriwave Lateral Shearing Interferometry (QLSI), to measure the temperature produced from the plasmon decay of gold nanoparticles. The advantages of QLSI compared to other approaches are it is non-invasive, does not require calibration, and has high thermal resolution. Here, I use QLSI to investigate the heat profile at decreasing nanoparticle densities and observe the transition from collective heating to single-particle heating. Temperature measurements with single-particle resolution may ultimately provide insights into how individual nanoparticle heating and collective heating influence plasmon-mediated chemistries.