Abstract
Light microscopy is one of the most powerful techniques for nondestructive real-time imaging of specimens at a resolution beyond the reach of human eyes. However, the spatial resolution of any conventional microscope is fundamentally limited by the diffraction of light waves at the lens aperture. Microsphere-assisted microscopy (MAM) has emerged in the past decade as an interestingly simple yet efficient method to improve imaging resolution. In MAM, a micrometer-scale dielectric sphere is placed in the immediate vicinity of the specimen to enhance the imaging resolution and magnification. MAM is highly versatile and can be combined with various systems including wide-field, confocal, and fluorescent microscopes to name a few. The exact resolution enhancement mechanism in MAM is not yet clearly understood and is under intense investigation; however, fundamentally, it can be linked to the increase in the system's effective numerical aperture and evanescence wave collection, and possibly to contributions from photonic nanojet effect, resonance, and coherent effects. Various claims have been made in the literature about the resolution gain in MAM, most of which are due to using arbitrary criteria for quantifying the resolution and possible contributions from specimen-specific parameters in imaging metallic nanostructures. In this Tutorial, we discuss the progress in MAM with special scrutiny of the imaging resolution.
Highlights
Light microscopy is one of the most powerful techniques for nondestructive real-time imaging of specimens at a resolution beyond the reach of human eyes
The spatial resolution of any conventional microscope is fundamentally limited by the diffraction of light waves at the lens aperture
The Blu-ray® disk (BD) sample and a conventional upright white-light microscope were used; Microsphere-assisted microscopy (MAM) was performed with a 220-μm-diameter barium titanate glass (BTG) sphere submerged in IPA; 2-mm-diameter hemispherical SILs (h-SILs) made of fused silica (n ∼ 1.458), N-BK7 (n ∼ 1.51), sapphire (n ∼ 1.77), and S-LAH79 (n ∼ 2) were studied in that work
Summary
Light microscopy is one of the most powerful techniques for nondestructive real-time imaging of specimens at a resolution beyond the reach of human eyes. Various microscopy techniques based on scanning near-field probes,[1] molecular fluorescence,[2,3,4] microscale and nanoscale solid immersion lenses,[5,6,7,8] structured illumination,[9] plasmonic structures,[10] and metamaterials[11] have been proposed to improve microscopy resolution. Those challenges can be overcome to some extent in some metamaterials;[19,20,21,22] they have their own restrictions: limited operational frequency range and absorption issues In this context, microsphere-assisted microscopy (MAM) emerged in the past decade as an interestingly simple, yet efficient approach to improve microscopy resolution.[23,24,25,26,27,28] In MAM, a microsphere is placed in the immediate vicinity of the object acting as a “magnifying glass” to improve the resolution.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
