Enhancing Super-Resolution Imaging of Semiconductor Materials Using a Linear Displacement Spectral Technique

Desman Perdamaian Gulo^1*, Te-Hsin Yen¹, Shang-Lin Jiang¹, Junichi Takara^2,3, Shi-Wei Chu^1,4,5

¹Physics, National Taiwan University, Taipei City, Taiwan
²Graduate School of Engineering, Osaka University, Osaka, Japan
³Photonics Center, Osaka University, Osaka, Japan
⁴Molecular Imaging Center, National Taiwan University, Taipei City, Taiwan
⁵Brain Research Center, National Tsing Hua University, Hsinchu, Taiwan

* Presenter:Desman Perdamaian Gulo, email:desmanpgulo@ntu.edu.tw

Mie resonances at the nanoscale offer powerful opportunities for photonic technologies, arising from strong electric and magnetic dipoles and higher-order multipoles that enable precise control of light scattering. Traditionally, Mie resonances are determined by structural dimensions relative to the excitation wavelength. Recently, a new concept of displacement resonance has been demonstrated, where shifting a tightly focused laser beam relative to a nanostructure excites multipole modes inaccessible under plane-wave illumination [Nat. Commun. 14, 7213 (2023)]. Here, we explore displacement resonance spectroscopy in silicon nanostructures as a linear optical technique to enhance spatial resolution by integrating a supercontinuum laser with confocal reflection microscopy. As the focal spot is displaced from the center toward the edge, the scattering spectra exhibit distinct resonance variations. Spectral ratio analysis between edge and center reveals a dominant displacement resonance, whose spectral position varies with nanostructure size. When the supercontinuum laser excites non-resonant wavelengths, laser scanning microscopy produces a Gaussian scattering profile, whereas resonant excitation generates a non-Gaussian pattern with dual side lobes and a central dip. Subtracting both profiles yields a sharpened intensity distribution with reduced full width at half maximum, approaching actual nanostructure size. This linear approach establishes a new avenue for super-resolution imaging through displacement Mie resonance spectral engineering that applicable to nanostructured materials.

Keywords: Super-resolution Imaging, Displacement Resonance, Semiconductor Materials