Nanoscopic visualization of chiro-optical field in photoinduced force microscopy

Abstract

Nanoscopic observation of chiro-optical phenomena is an intriguing scientific topic but have large difficulties in the measurements, and hence the physics is still largely unexplored. So far, the chiro-optical physics have not been well unveiled; conventionally, those phenomena have been investigated only through indirect information from the macroscopic far-field optical measurements and/or predictions by theoretical simulations. To fully understand and to utilize the full potential of chiro-optical systems, the local in-situ observation of the effects from individual components is essential, as the macroscopic chiro-optical effect is not straightforward for the analysis of the microscopic phenomena.In the present study, we attempted the imaging of the chiro-optical forces confined in the nanospaces based on a photoinduced force microscopy. On the right-handed gammadion structure, the strong optical gradient force appeared at the edges of the structure under illumination of LCP light at 785 nm. The left-handed gammadion gave the similar result under RCP illumination. This research paves the way for clarifying the physics of nanoscale chiro-optics and application of that.