Supercontinuum (SC) generation has attracted a significant scientific interest in the past decades due to its promising applications covering the fields of metrology, spectroscopy, defense, as well as medical treatments. To date, researchers are devoted to improving the spectral width and flatness of SC generation by using specialty optical fibers. The flatness of the spectrum is of importance because it can improve the accuracy of measurement in practical applications. This paper summarizes the theory of SC, the state of the art of flat SC generation using optical fiber including photonic crystal fibers, soft glass fibers as well as germania-doped fibers, and suggests the future research direction of flat SC light source.of Shanghai.

Optical axial scanning is essential process to obtain 3D information of biological specimens. To realize optical axial scanning without moving, the tunable lens is a solution. However, the conventional tunable lenses usually induce non-uniform magnification and resolution issues. In this paper, we report a movable electrowetting optofluidic lens. Unlike the conventional tunable lens, our proposed optofluidic lens has two liquid-liquid (L-L) interfaces, which can move in the cell by an external voltage. The object distance and image distance are adjusted by shifting the L-L interface position. Therefore, the proposed lens can realize optical axial scanning with uniform magnification and resolution in microscopy. To prove the concept, we fabricate an optofluidic lens and use it in optical axial scanning. The scanning distance is more than 1 mm with uniform magnification and good imaging quality. Widespread application of such a new adaptive zoom lens is foreseeable.