“Natural science, does not simply describe and explain nature; it is part of the interplay between nature and ourselves” – Werner Heisenberg
Our group has a diverse research interest but primarily focuses on light-matter interactions at small (micro, nano, molecular, and atomic) scales. Many of our research topics are in the field of metamaterials and nanophotonics. Also, we are interested in materials science, particularly in two-dimensional (2D) materials, such as graphene, black phosphorus, and transition dichalcogenides (TMDs).
The discovery of new materials or new technologies designates a new era, for instance, the Bronze age and the Iron age. At the turn of this century, a new technology emerged to design materials by artificially arranging structures at a subwavelength scale. Instead of obtaining material properties by chemical compositions, this new technology relies more on geometrical designs that are readily achievable through modern semiconductor manufacturing facilities. As a result, this technology has considerably extended materials space beyond the scope of natural materials, and it is named metamaterial (from the Greek word μετά meta, meaning “beyond”). Exploring these areas is of great importance for both fundamental physics and practical applications. We are particularly interested in this exciting frontier in optics and photonics. For example, we have applied a thin metamaterial to enable augmented reality on contact lenses towards dramatically reduced device footprint. With optical functionalities by design, it is arguably safe to say that photonics enters a new era named “metaphotonics.”
For a scientist, nothing is more exciting than contributing to human knowledge by breaking a limit. One such limit in optics is the “diffraction limit,” which indicates that it is impossible to distinguish two objects with a distance smaller than half of the optical wavelength. Excluding super-resolution microscopy playing with the time, a possible solution is to use plasmonics on the surfaces of metals (typically gold and silver) by harvesting the near-field momenta. Unfortunately, like eating fish while dealing with the fishbone, the plasmonics needs to deal with the Ohmic loss of metals. Most of the applications temp to live with it by looking at the bright side that the loss is not necessarily harmful. We are optimistic about plasmonics for recognizing the conventional role of a plasmonic metal as a conductor to conduct electric signals. And hence, the plasmonic devices can have dual optical and electrical functionalities simultaneously that are promising for nanoscale plasmonic circuitry. We have found some niche applications in nonlinear optics and plasmoelectronics.
Their strong in-plane bonding and relatively weak out-of-plane van der Waals forces have made it possible to exfoliate layered 2D materials down to one or only a few atoms in thickness. At this atomic scale, many exotic physics and phenomena emerge. We are interested in the fundamental study of light-matter interactions and quantum information science in 2D materials. A critical factor in advancing this research field is to modulate material properties beyond what they traditionally offer. Rather than modifying 2D materials themselves, we surround them with engineered photonic environments. We investigate local and topological effects in both the weak and strong coupling regimes. We also translate and exploit 2D materials for future technologies with a small device scale, fast operating speed, and low energy consumption. For instance, we have integrated the separation, analysis, and detection of the full-Stokes polarization of light in a monolithic graphene-silicon-metamaterial device.