Tunable Opto-Chemical Virtual Aperture Induced by Azobenzene Cis-Trans Isomerization

This paper presents an innovative approach utilizing the optical isomerization of azobenzene polymer films, which markedly diminishes the spatial dimensions of the focused light spot. By manipulating the power ratio of two distinct wavelengths of laser, the light-induced alignment of azobenzene molecules within the polymer film can be modified, thereby enabling the development of an “opto-chemical virtual aperture” that effectively reduces the size of the focused light spot. Simulations assess the direct impact of laser power ratios on the orientation of azobenzene molecules, while the experimental findings indicate significant variations in the dimensions of the light spot in response to these changes. The validation of the fundamental characteristics of azobenzene is crucial for the progression of optical micromachining techniques beyond the diffraction limit and for advancements in near-field optical manipulation.