Microsphere-assisted microscopy

Light microscopy is one of the most powerful techniques for nondestructive real-time imaging specimens at a resolution beyond reach human eyes. However, spatial any conventional microscope fundamentally limited by diffraction light waves lens aperture. Microsphere-assisted (MAM) has emerged in past decade as an interestingly simple yet efficient method to improve resolution. In MAM, micrometer-scale dielectric sphere placed immediate vicinity specimen enhance and magnification. MAM highly versatile can be combined with various systems including wide-field, confocal, fluorescent microscopes name few. The exact enhancement mechanism not clearly understood under intense investigation; however, fundamentally, it linked increase system's effective numerical aperture evanescence wave collection, possibly contributions from photonic nanojet effect, resonance, coherent effects. Various claims have been made literature about gain which are due using arbitrary criteria quantifying possible specimen-specific parameters metallic nanostructures. this Tutorial, we discuss progress special scrutiny