Seminar : Near field Microwave and Optical Microscopy
Davide Mencarelli, Ph.D.
UPVM (Universita Polytechnica delle Marche) in Ancona (Italy)
Friday 1st june 2018 – 2pm
IEMN – LCI Salle du conseil – Villeneuve d’Ascq
Scanning Probe Microscopy (SPM) includes a wide class of different techniques united by the fact that a probe is scanned over a sample surface to build up high-resolution images. The latter can normally visualize different properties of the sample, because different probe-sample short-range interactions can be exploited. Atomic Force Microscopy (AFM) and Scanning Tunneling Microscopy (STM) are very common examples of such techniques. Another very remarkable example is provided by Scanning Microwave Microscopy (SMM), where the probe-sample interaction, still given by atomic force or by tunneling current, is augmented by e.m. evanescent fields, featuring rapid decay from the probe tip. The additional information provided by the electromagnetic interaction, usually in the form of a recorded reflection coefficient, constitutes a useful mean to investigate high frequency properties of sample surface, e.g. dielectric constant, resistivity, dispersion.
The above characterization is also useful for current research on nanomaterial and nanoparticles, which include biologic and medical targets, such as drug delivery and antibacterial applications. An interesting example is given by SMM scan of breast cancer cells MCF-7 treated by fullerene (C60), with a simultaneous topographic and electromagnetic characterization of sample surface. Calibration of SMM data is necessary in order to isolate the probe-sample interaction, and to possibly disentangle the topography from the electromagnetic response of the sample. Use of microwave microscopy could be crucial to investigate the effects of fullerene treatment, and could enable, in the future, deep imaging of its penetration inside the cells.