Description

Resonant waveguide grating (RWG) is a typical dielectric structure, which contains single or multi-layer layer of planar waveguide and its top surface textured with one-dimensional or two-dimensional subwavelength grating. Guided mode resonance (GMR) is an important optical property of RWG, which occurs when the incident light diffracted by the grating is coupled to a waveguide mode of the waveguide layer. When a GMR condition is fulfilled, a sharp reflection and near-zero transmission anomaly is formed at a specific wavelength and incident angle. This allows many applications in different domains, such as multiple bandpass filters, tuneable laser, bio/chemical sensors, etc.

In this project, we propose to realize all polymer-based RWG structures, which have different advantages, such as rapid fabrication, simple and low cost, easy to be functionalized and optically integrated, etc. However, in order to localize the light field strongly on the free surface of the RWGs, which is practically important for applications, it requires that the refractive index of the lower layer of the RWG has lower refractive index. We therefore propose to elaborate a new porous polymer material with a controllable refractive index, lower than 1.55.  Besides, in order to obtain multiple periodicities in the same RWG structure, we propose to use the one-photon absorption (LOPA) based direct laser writing (DLW). The multiple resonant RWG enables new applications such as multiple modes laser, multiple wavelengths sensors and bandpass filters, based on simple all-polymer-based RWGs.