Nanofiber Integrated with Quantum Dots

A research team from the Center for Photonic Innovations at the University of Electro-Communications has integrated quantum light sources with nanofibers, a possible step toward a quantum Internet.

A computer-controlled picoliter liquid dispenser and an inverted microscope were used to deposit individual quantum dots along the fiber, which is 400 nm in diameter and has 99 percent light transmission.

A composite photonic crystal cavity formed by combining an optical nanofiber and a nanofabricated grating. Courtesy of the Center for Photonic Innovations.

The dot deposition resulted in spatial accuracy better than 3 µm and photon channeling efficiency of 22 percent.

The technology can integrate with conventional fiber-based communication networks, the researchers said.

“The femtosecond-laser-fabricated photonic crystal nanofiber cavities coupled with cold atoms can realize various manipulation methods of single photons, which offer the basic tools for the next generation of Internet communications,” the researchers wrote in a study published in Physical Review Letters (doi: 10.1103/PhysRevLett.113.143601).

The team was supported by the Japan Science and Technology Agency, the Strategic Innovation Program and Ishihara Sangyo Inc., which provided the fibers.

For more information, visit www.uec.ac.jp.