Sum Frequency Microscopy of Phonon Polaritons

PC Online Talk
Date: Feb 11, 2021
Time: 11:00 AM (Local Time Germany)
Speaker: Dr. Sören Waßerroth
FHI Department PC

Sum frequency generation (SFG) allows the study of surfaces and inversion broken systems. In a new approach we implemented a wide field sum-frequency microscope combining the FHI infrared free electron laser (IR FEL) as excitation source with visible upconversion. The IR FEL provides a powerful, narrow band, and tunable light source [1]. By direct imaging of the SFG light with a microscope in a wide field scheme without scanning the sample or the focus [2], we achieve a spatial resolution well beyond the infrared diffraction limit.

I will show first microscope images of phonon polariton resonances in subdifractional SiC structures. Full spectral mapping of the structures allows spectroscopic identification of the various polariton resonances. Additionally, the high spatial resolution of the microscope (< 1 µm) resolves the modal structure of polaritons within the different structures. We follow the evolution of the polariton modes by varying the geometrical parameters.
[1] Schöllkopf et al., Proc. of SPIE (2015)
[2] Kiessling et al., ACS Photonics, (2019)

Join Zoom Meeting
https://zoom.us/j/96044929805?pwd=dU5RUm5hMTNsUDR4VnBBOTJKSGJWdz09
Meeting-ID: 960 4492 9805
Passcode: 330122