Fabrication of lithium niobate metasurfaces via a combination of FIB and ICP-RIE

Lithium niobate (LN) metasurfaces have emerged as a new platform for manipulating electromagnetic waves. Here, we report a fabrication technique for LN nano-grating metasurfaces by combining focused ion beam (FIB) milling with inductively coupled plasma reactive ion etching (ICP-RIE). Steep sidewalls with angles larger than 80 degrees are achieved. Sharp quasi-bound states in the continuum are observed from our metasurfaces. The measured transmission spectra show good agreement with the numerical simulations, confirming the high quality of the fabricated metasurfaces. Our technique can be applied to fabricate the LN metasurfaces with sharp resonances for various applications in optical communications, on-chip photonics, laser physics, sensing, and so on.

Automated summary

A fabrication technique combining focused ion beam milling and inductively coupled plasma reactive ion etching is used to produce lithium niobate nano-grating metasurfaces with steep sidewalls. The fabricated metasurfaces exhibit sharp quasi-bound states in the continuum and have good agreement with numerical simulations. This technique has potential applications in optical communications, on-chip photonics, laser physics, and sensing.