The next webinar in the Monash Centre for Electron Microscopy series is ‘Seeing Trapped Light at the Nanoscale’ presented by A/Prof. Michel Bosman, Materials Science and Engineering at the National University of Singapore and the Institute of Materials Research and Engineering, A*STAR, Singapore.
A/Prof. Michel Bosman research focuses on visualizing materials at the atomic scale using aberration-corrected scanning TEM (STEM), and on light spectroscopy at the nanometer length scale with monochromated electron energy loss spectroscopy (EELS) and STEM-cathodoluminescence.
There is a great difference in appearance between a smooth surface and a fine-textured surface. This difference becomes even more striking when we fabricate surfaces with features that are much smaller than the wavelength of light. Nanopatterned surfaces can be designed to absorb specific energy bands, have polarization-dependent colour, or it may be able to trap light. These properties can be engineered by controlling one or more resonant modes, such as Mie resonances, surface plasmon resonances and bound states in-the-continuum.
In this presentation, it will be shown that electron microscopes can be a unique and useful tool to measure optical properties at the nanometer length scale. It will be shown that monochromated STEM-EELS can be used to measure femtosecond electron dynamics in plasmons, with nanometer spatial precision! By combining EELS and STEM-cathodoluminescence measurements, it is also possible to visualize light that is trapped on surfaces. From these non-radiative, so-called bound-states-in-the-continuum, we can now even directly measure the coherent interaction length.
This work would not have been possible without the invaluable contributions from Hue Do (NUS), Dong Zhaogang (IMRE, A*STAR), Zackaria Mahfoud (IMRE, A*STAR) and Joel Yang (SUTD, IMRE). Funding from the Ministry of Education (MOE) Singapore, under AcRF Tier 2 (MOE2019-T2-1-179), and AcRF Tier 1 (R-284-000-179-133) is kindly acknowledged.
If you have any questions about the presentation please direct them to mcem@monash.edu
