The nanomembrane and topological photonics focuses on the design and fabrication nanomembraned-based photonic structures such as optical microcavities and photonic lattices for both fundamental and applied research ranging from cavity photonics, non-Hermitian and topological photonics, optoplasmonics to photonic integration.
We have proposed and systematically investigated the manipulation of 3D optical resonances in self-assembled nanomembrane-based microtubular cavities. To obtain high yield, reproducibility and quality fabrication at wafer scale, a dry-release approach has been developed to roll-up both metallic, dielectric as well as metallic/dielectric hybrid thin films for the fabrication of electronic and photonic devices. By carefully modifying the cavity structures and the cavity media, unique phenomena such as 3D optical coupling, mode chirality, directional light emission and 3D lasing can be realized. Manipulation of light flow in overlapping potential wells and parallel neighboring resonant orbits were investigated, which is of high significance for exploring optical hybridizations in novel types of photonic structures. We are also interested in the manipulation of light in hybrid photonic-lattice-on-tube systems, 2D materials in microcavities, on-chip integrated composite cavities, and phase transitions probed by optical resonances.
Optical microcavity system is known as an excellent platform to manipulate the light flow and investigate non-Hermitian physics in open optical systems. For whispering gallery mode optical microcavities, modifying the rotational symmetry is highly desirable for intriguing phenomena such as degenerated chiral modes and directional light emission. A precise engineering of cavity boundary can enable the transition between clockwise and counter clockwise traveling-wave components and the tuning of light out-coupling channels. These researches are of high interest for understanding rich insights in non-Hermitian photonics and unfolding exotic properties on lasing, sensing, and cavity quantum electrodynamics.
Optical spin-orbital coupling in microcavities such as asymmetric microcavities and Möbius ring cavities can result in the occurrence of Berry phase. The generation of optical Berry phase in whispering-gallery mode microcavities leads to the existence of non-integer numbers of resonant modes, providing a topological quantity for microcavity-based signal processing and optical communication. This research introduces non-trivial topology to the field of optical microcavities, and may lead to many promising applications in microcavity-based signal processing and quantum information technologies. We are also working on in-situ topological phase transition enabled in specially designed photonic lattices.
The coupling between surface plasmons and cavity resonant modes can be explored by designing metallic nanostructures on microcavities surface. This research investigates the interaction of surface plasmon resonances localized at the nanoscale with optical resonances confined at the microscale, thus establishing a unique platform for the investigation of light-matter interactions. We are also interested in investigating the combination of plasmonic crystal lattice and optical microcavity for band structure modified optical coupling. These researches pave the way for manipulating the photon-plasmon coupling in specially designed hybrid optoplasmonic system, forming the core of controllable light-matter interactions in practical applications.
Based on thin-walled microtubular cavities, nanoclusters and dynamics of molecular multilayer on oxide surfaces can be in-situ detected. This research addresses fundamental questions regarding the nanostructure and dynamics of molecular layers on oxide, for example, to reveal how a molecular multilayer grows and desorbs as it is thermally activated. With this investigation, a versatile platform can be developed to investigate surface molecular dynamics and chemical reactions in both low temperature and room temperature. This research would pave the way for real-time, high-precision analysis of molecular dynamics by resonance-based optical microcavities.
On-chip integrated microdevices fabricated via self-rolling of structured nanomembranes have been studied for photonic applications. Out-of-plane optical coupling can be realized by integrating microtube cavities onto planar rings and waveguides, which offers new options for 3D photonic integration schemes. We have demonstrated selective mode coupling between resonant modes supported by a microtube cavity in a vertical plane and in-plane resonances of planar racetrack microring resonators. The fundamental and higher-order axial modes confined in the microtube cavity are selectively coupled with the resonances in the microring by using the degree of freedom of the tube axial dimension. This investigation is not only interesting for fundamental reasons such as the optical strong coupling of higher-order modes, but also promising for practical applications in new 3D photonic integration schemes.
