Flexible guided-wave manipulation using phase-gradient dielectric metasurface antenna array

Metasurface has been deemed as a promising way in integrated optics to manipulate the guided wave. In this paper, we demonstrate the capability of manipulating the amplitude, phase, and polarization of the light in waveguides using the phase-gradient dielectric metasurface antenna array. Using fundamental TE mode as input, we design and simulate two bimodal interferometers that generate two guided modes with tunable intensity percentages and a quasi-circular polarization generator. For bimodal interferometers, the two interferometers have the output of the hybrid TE0–TE1 modes and TE0–TE2 modes with identical intensity, respectively. Two groups of the hybrid modes separately interfere in the waveguides and generate two and three hot spots in the transverse direction. The mode purities of all modes for both two bimodal interferometers are higher than 47.35%. The power transmissions for TE0–TE1 modes and TE0–TE2 modes interferometers are 69.7% and 70.3%. For quasi-circular polarization generator, we generate the hybrid TE0–TM0 modes with a 87.3° phase difference. The mode purities for the two modes are higher than 44.91%, and its power transmission is 69.1%. By arranging the number and distributions of the meta-atoms in the antenna array, we can flexibly tailor the constituent of waveguide modes with low budget.Graphical abstract