Microsphere-Assisted Imaging of Periodic and Non-Periodic Structures

In this work, the difference in imaging small clusters of nanoparticles and hexagonally close packed nanoparticle arrays by microsphere-assisted microscopy is studied. For both high-contrast samples and low-contrast ones, compared with small cluster samples, a better image quality and a larger lateral magnification are observed when imaging periodic array samples. We propose that in imaging periodic samples, the evanescent waves carrying high-frequency information can be converted into propagating waves by shifting the incident wavevectors into different diffraction orders. Therefore, more high-frequency information of the samples can be collected by the imaging system, which results in an improved image quality and a larger magnification when observing periodic array samples.