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 also show that long nanojets can be formed using semiconductors at infrared frequencies in free space.
© 2014 Optical Society of America
Original Manuscript: May 15, 2014
Manuscript Accepted: June 4, 2014
Published: July 7, 2014
Yuecheng Shen, Lihong V. Wang, and Jung-Tsung Shen, "Ultralong photonic nanojet formed by a two-layer dielectric microsphere," Opt. Lett. 39, 4120-4123 (2014)