Title: "Nanostructured On-Chip Photonics: All-Dielectric Metamaterials and Frequency Combs"
Photonic chips can confine light in nanoscale and have revolutionized photonic research by increasing the light-matter interactions. The compatibility with well-established CMOS manufacturing technology makes silicon photonics promising; however, there are still challenges in this area with the large device sizes (compared to nanometer-scale electronic transistors) due to waveguide cross-talks and bending losses.
In this talk, I will present my two recent research projects: 1) frequency comb generation with dispersion-engineered concentric microresonators  and 2) photonic skin-depth engineering with all-dielectric metamaterials . First, concerning the frequency comb research, I will present a concentric resonator that can engineer and significantly modify the dispersion. Strong anomalous dispersion has been demonstrated in a thin silicon nitride film which was previously thought to have high normal dispersion, and consequently unsuitable for frequency comb generation. Together with a mode-selective, tapered coupling scheme, coherent frequency combs and soliton pulses have been generated. Next, I will present a method to engineer the skin-depth of photonic waveguides using all-dielectric metamaterials. A new class of waveguide scheme, i.e., extreme skin-depth (e-skid) waveguide is introduced, and I experimentally demonstrate e-skid waveguides that reduce the waveguide cross-talks and bending losses significantly, thus enabling dense integration of optical waveguides on a chip.
Sangsik Kim is an assistant professor in the Department of Electrical and Computer Engineering (ECE) at Texas Tech University. Previously, he was a postdoctoral research associate in the Center for Nanoscale Science and Technology (CNST) at the National Institute of Standards and Technology (NIST). He was also a postdoctoral researcher in ECE at Purdue University, where he received a MS and a PhD. He received his BS in ECE from Seoul National University, South Korea. His research interests include the development of novel photonic devices and their applications, which encompass on-chip Kerr frequency combs, high-density photonic integration, metamaterials and plasmonics, passive/active photonics, and nonlinear/quantum photonics.
*Refereshments will be served prior to the colloquium*