Advantages of microsphere-assisted super-resolution imaging technique over solid immersion lens and confocal microscopies

We demonstrate a series of advantages of microsphere-assisted imaging over confocal and solid immersion lens microscopies including intrinsic flexibility, better resolution, higher magnification, and longer working distances. We discerned minimal feature sizes of ∼50-60 nm in nanoplasmonic arrays at the illumination wavelength λ = 405 nm. It is demonstrated that liquid-immersed, high-index (n ∼ 1.9-2.1) spheres provide a superior image quality compared to that obtained by spheres with the same index contrast in an air environment. We estimate that using transparent microspheres at deep UV wavelengths of ∼200 nm might make possible imaging of various nanostructures with extraordinary high ∼30 nm resolution.