Enhancing Coherent Superoscillatory Microscopy through Complex Deconvolution

Superoscillation is a phenomenon in which parts of a signal oscillate at a frequency higher than its highest Fourier component. By utilizing a superoscillatory (SO) point-spread function, an SO imaging system has the potential to capture high-frequency details, thereby overcoming the diffraction limit. In this study, we introduce an approach that integrates coherent SO microscopy with a complex deconvolution method. The system employs a HeNe laser with a wavelength of 632.8 nm for illumination and operates with a numerical aperture of 0.3. The object imaged is a chrome-on-glass mask featuring letters. By incorporating the phase-shifting interferometry technique into this microscopy system, the phase information can be obtained. Utilizing complex Wiener deconvolution, the resolution of restored SO imaging under coherent illumination is enhanced by a factor of approximately 2 beyond the restored diffraction limit, achieving a critical interspace of 0.32 μm for the letter A. Additionally, the proposed approach allows us to image both extended and phase objects, expanding its range of potential applications.