Photonic-molecule light and Super-nonlinear optical metamaterials

This talk covers two topics of our research on nonlinear optics: Photonic-molecule light and Super-nonlinear optical metamaterials.

Photons rarely interact. Even in natural nonlinear optical media, in which two light beams can interact because of their influence on the medium's refractive index, this interaction is still prohibitively weak at typical light levels. If photons could be effectively bonded through photon-photon interactions, the resulting many-photon system could exhibit a number of novel features that would enable a multiplicity of profound applications. We predicted that photons could form bound states — the photonic molecules — which manifest effective inter-photon attractions and represent the most fundamental quantum nonlinear photonic entities. The existence of the photonic molecules was subsequently experimentally confirmed. In the first part of the talk, I will explain the physics of photonic molecules and the efficient generation mechanisms. I then will describe how an ensemble of photonic molecules would shed some new light on the realization of efficient low-power two-photon excitation, optical super-resolution, deep tissue imaging, superradiance, and quantum photonic materials.

The switching speed of all optical binary switching schemes to date is much lower than the switching speed of electrical transistors. The principal inhibiting factor is the lack of strong nonlinear optical materials. In the second part of the talk, I will describe our work on super-nonlinear metamaterials, which are structured optical materials with an extraordinarily enhanced nonlinearity that is 1,000 times better than normal nonlinear materials. As the materials spatially compress the light signal by using subwavelength low-Q channels, instead of temporally trapping the signal in high-Q cavities, the materials have an ultra-short switching time of 5 picoseconds. The super-nonlinear materials are also broadband and optically thin, and thus are ideal for ultrafast and configurable Boolean optical logic gates.
Jung-Tsung Shen received his PhD in Physics from MIT, and did his Postdoc in the Electrical Engineering Department and the Ginzton Lab at Stanford University. He received the 2013 NSF CAREER Award, Bear Cub Entrepreneur Award, and the Bell Labs Graduate Fellowship. His research focuses in quantum nano-photonics and metamaterials address some of the major challenges in optical science and optical engineering. Together with his research group, he proposed the concepts of photonic molecules, single-photon diode, single-photon frequency converter, ultra-high refractive index metamaterials, and super-resolution using metamaterials. All his key predictions are experimentally confirmed.