Tuesday 4 December 2018 16:00 – 17:00 Seminar Room 1
” Polarization-resolved second harmonic generation (P-SHG) imaging microscopy and applications”
Dr. Sotiris Psilodimitrakopoulos Institute of Electronic Structure and Laser (IESL)
Traditionally, analysis of second harmonic generation (SHG) imaging has been achieved by evaluating the strength of the generated SHG signal, used for contrast. While non-linear signals intensities remain the “gold standard” for microscopists, this approach is inherently highly subjective, as the accuracy depends on the experience and skill of the interpreting scientist. There remains a clear need for quantitative, optical microscopy approaches that eliminate the artifacts inherent in the interpretation of SHG signal intensities. Towards that goal, we utilized polarization analysis of the SHG signals to probe the orientational information of the implicating SHG active assemblies. In particular, we upgraded a regular Zeiss fluorescence microscope into a fully-motorized polarization-resolved multi-photon microscope, using an Yb:KGW femtosecond laser, galvanometric mirrors and photomultiplier tubes, as well as retardation plates, analyzers, appropriate electronics, optics and filters1 (Fig.1). In this seminar, after introducing the raster-scanning imaging microscopy technique I will demonstrate how polarization-resolved SHG (P-SHG) imaging can be used for the detailed evaluation of crystal quality in 2D transition-metal dichalcogenide (TMD) materials as well as other applications of P-SHG imaging.