< BK21+ BEST Seminar Series Announcement> 

Time and Date : 11:00 ~ 12:00 Friday 08/10/2018

Place : B701, Engineering Building #2

Title : Nanostructured on-chip photonics with all-dielectric metamaterials and concentric microresonators

Abstract:

Chip-scale photonic devices can miniaturize a bulk optical system into a single tiny chip, confining light down to hundreds of nanometer-scale waveguide cross-sections and enhancing the light-matter interaction; this has revolutionized the fundamental research in nonlinear/quantum photonics. In addition, a compact, chip-scale device size allows the use of photonic systems outside of the laboratory for a broad range of applications in high-speed optical communication, biochemical sensing, high-precision spectroscopy, light detection and ranging (LIDAR), etc. In such applications, realizing a high-density photonic chip integration is highly desirable, as more building blocks provide more functionalities on a single chip (analogous to electronics). However, current approaches of light confinement simply rely on the index-contrast of core and cladding materials and the wave nature of light (e.g., waveguide crosstalk) limits the photonic integration density.

In this talk, I will review our efforts in developing novel photonic devices: 1) high-density photonic chip integration with all-dielectric metamaterials [1] and 2) on-chip microcomb generation with dispersion-engineered concentric microresonators [2]. First, I will present a new class of waveguide scheme, i.e., an extreme skin-depth (e-skid) waveguide, whose evanescent waves are suppressed by highly anisotropic all-dielectric metamaterials. The waveguide crosstalk and bending loss are reduced significantly, enabling a dense integration of optical waveguides. Next, concerning the frequency comb research, I will present a concentric microresonator that can engineer the resonator dispersions significantly. Strong anomalous dispersion has been demonstrated in a thin silicon nitride film which was previously thought to have high normal dispersion. Together with a mode-selective, tapered coupling scheme, coherent frequency combs and soliton pulses have been generated. Finally, I will briefly describe a photonic to free-space extreme mode converter for the integration of photonic chips with other systems, e.g., atomic vapor cell cavities.

Presenter: Sangsik Kim, Assistant Professor / Texas Tech University, United States

Host: Prof. Choi, Wooyoung, Yonsei EEE