ľ¹Ï¸£ÀûÓ°ÊÓ

Title: Photonic artefacts in luminescence nanothermometry

Abstract: Nanocrystals with temperature-sensitive luminescence become increasingly popular as thermometers. Excitation and detection of the luminescence occurs remotely, which makes this a versatile and user-friendly thermometry technique. In principle, it only requires a fluorescence microscope to map the temperature of luminescent nanocrystals, embedded in a sample, with a diffraction-limited spatial resolution. However, photonic effects and higher order excitation processes that may occur for the highest resolution mapping can distort the luminescence spectra, resulting in incorrect temperature readout.

In this lecture, I will discuss how these issues affect the accuracy of nanothermometers that are deposited on a microelectronic heater and on a mirror coated with a spacer of variable thickness. The temperature maps recorded on the heater reveal clear signs of artefacts due to inhomogeneities of the photonic environment and high excitation intensities necessary for sub-μm resolution. While correcting for these artefacts is possible in static samples, measurements in dynamic media face inherent read-out errors due to the photonic environment. The mirrors with variable spacer thickness enabled us to systematically study this and identify the experimental parameters that minimize photonic artefacts. These findings are not only relevant for the application of temperature sensors but are also important for the development of other optical sensing methods.

Based on published paper:

T.P. van Swieten, T. van Omme, D.J. van den Heuvel, S.J.W. Vonk, R.G. Spruit, F. Meirer, H.H. Pérez Garza, B.M. Weckhuysen, A. Meijerink, F.T. Rabouw, R.G. Geitenbeek, ACS Applied Nano Materials, 4, 4208–4215 (2021)