Ultralong photonic nanojet formed by a two-layer dielectric microsphere

Yuecheng Shen, Lihong V. Wang, Jung-Tsung Shen
2014 Optics Letters  
A photonic nanojet is a highly focused optical beam with a subwavelength waist on the shadow side of the sphere. Successful far-field applications require long nanojets that extend afar. Using the exact Mie theory, we show that ultralong nanojets can be generated using a simple two-layer microsphere structure, using conventional optical materials that are readily available. In particular, we show that for a glass-based two-layer microsphere, the nanojet has an extension of 22 wavelengths. We
more » ... wavelengths. We also show that long nanojets can be formed using semiconductors at infrared frequencies in free space.
doi:10.1364/ol.39.004120 pmid:25121666 fatcat:dtepke243feyph622f5e3l77ya