Integrated Photonic Materials and Devices

Integration is the main developing trend of photonic materials and devices. Currently, silicon photonic integrated circuits (PICs) and optical metasurfaces require optical thin films instead of bulky crystals, as well as planar integrated micro and nanophotonic devices instead of discrete components. In the micro and nano scale, new physical phenomena emerge when light and matter interact. The structure and fabrication method of optical thin films diverse from their bulk counterparts; and the device structure and operation principle are vastly different. Our group dedicate in studying the mechanism between light and matter interaction at the nanoscale. We study heterogeneous integration of key optoelectronic and optomagnetic materials on silicon. We also develop heterogeneously integrated silicon PICs and optical metasurfaces with the aim of application in next generation optical communication, data communication and optical sensing microsystems.

1. Nonreciprocal Photonics

     Nonreciprocal photonic devices including optical isolators, circulators and phase shifters based on magneto-optical thin films are key components in photonic systems. They are widely used in optical communication, data communication and optical sensing. However, the principle of nonreciprocity in nanoscale photonic structures is unclear. The technology to integrate magneto-optical thin films and devices on semiconductors is not mature, causing such materials and devices absent in photonic chips, which is recognized as the “fundamental challenge for integrated photonics”.

    Our group study the new nonreciprocal photonic mechanism in magnetic nanophotonic structures. We heterogeneous integrate magneto-optical thin films on silicon. We develop silicon waveguide based nonreciprocal photonic devices. We aim to apply these materials and devices in optical communication, data communication and optical sensing technologies.

     2. Active Optical Metasurface

Based on the generalized Snell's law, optical metasurfaces allow planar integration of three dimensional photonic devices, such as prisms and lens, on a two dimensional surface. Active optical metasurfaces consist of functional photonic thin films  based metaatoms, allowing manipulation of optical properties of optical metasurfaces by external stimuli. Active optical metasurfaces are potentially applicable for  optical imaging, sensing and optical computing applications.

Our group dedicate to studying the light-matter interaction in active optical metasurfaces. We fabricate active optical metasurfaces based on magneto-optical, electro-optical and phase change materials for functionalities including polarization-tunable metasurfaces, focus-tunable metalens and reconfigurable diffractive metasurfaces. 

     3. Ferroelectric Photonics

Ferroelectric materials such as LiNbO3, BaTiO3 and HfO2 show electro-optical Pockels effect and nonlinear photonic effect. They are highly desired in next generation optical modulation devices. The goal of this field is to develop high electro-optic coefficient, low loss and silicon photonic process compatible ferroelectric thin films and integrated devices.

Our group dedicate to studying heterogeneously integrated ferroelectric thin films on silicon. We develop silicon waveguide integrated optical modulators and nonlinear photonic devices. We aim to apply these materials and devices in optical communication and data communication technologies.