Bioinspired Conformal Transformation Acoustics (PR Applied 2020)
In this paper, we propose a bioinspired semianalytical conformal acoustics that can predict the evolution of acoustic functions strictly. Based on this method, we design a series of acoustic steering and collimation models. The proposed bioinspired conformal acoustics may bridge the gap between an animal’s biosonar and artificial materials, which show potential application value in underwater acoustics, medical ultrasonography, and other related applications.
Transformation Caustics (PR Applied 2019)
In this article, we propose transformation caustics by applying coordinate transformation to the caustic effect. The limit boundaries of caustics can be used to design devices with asymmetric light propagation or light confinement, thus providing an alternative degree of freedom for metamaterials.
Light rays and waves on geodesic lenses (Photonics Research 2019, in collaboration with Dr. Lin Xu, Profs. Tomas Tyc, Hui Liu and Shining Zhu)
We demonstrate that light rays confined on geodesic lenses form closed trajectories, and that for optical waves, the spectrum of a geodesic lens is (at least approximately) degenerate and equidistant with the numerical method. Moreover, we fabricate two geodesic lenses in micrometer and millimeter scale and observe curved light rays along geodesics.
Broadband cloaks for Water Waves (PRL 2019, On the cover, Editors' Suggestion, and Featured in Physics, in collaboration with Prof. Zhenyu Wang from Zhejiang University)
Inspired by electromagnetic waveguide cloaks with gradient index metamaterials, we fabricated a broadband cloak with simply a gradient depth profile on the bottom and without any other structures on the top to confine water waves in a certain area for cloaking regions. Being easy to construct, this design is potentially of significance for port applications.
Inverse transformation optics design (PR Applied 2019, in collaboration with Profs. Hui Liu and Shining Zhu from Nanjing University)
In this article, we proposed the "inverse transformation optics", and found that a conformal singularity of a refractive-index profile, with either zero or infinity resulting from a power mapping w=z^a, is equivalent to a topological defect with positive charge or negative charge. We fabricated a "hat" shape device with such a topological defect with positive charge in experiments and its related light-bending functionality with laser beams.
Universal multimode waveguide crossing (Optica 2018, in collaboration with Prof. Dingshan Gao from Huazhong University of Science and Technology)
We demonstrate for the first time a universal multimode waveguide star crossing based on transformation optics, which can handle in principle any number of waveguide modes and any number of crossing channels as well. The structure is transformed from a Maxwell’s fisheye, which could realize aberration-free imaging for each waveguide mode. A grayscale E-beam lithography is adopted to fabricate it on commercial silicon-on-insulator wafer. The proposed multimode waveguide star crossing has little loss and low crosstalk throughout an ultra-broad wavelength range of ~400 nm. Our study paves the way for realizing highly integrated and large capacity on-chip multimode routing and communication systems.
Imaging along conformal curves(PRA 2018)