研究目的
To provide a crystalline silicon metasurface scheme to efficiently modulate transmitted light beams at visible wavelengths, specifically at 532 nm, using high-contrast grating (HCG) for full 2π phase control.
研究成果
The study demonstrates a high-efficiency deflective metasurface based on crystalline silicon HCG at 532 nm, achieving a deflection efficiency of 62%. This approach offers advantages over traditional materials like TiO2 and poly-Si, including lower aspect ratio and higher transmission in the visible range.
研究不足
The study is limited by the optical loss of dielectric materials in the visible regime and the requirement for precise fabrication techniques to achieve the desired phase control with c-Si metasurfaces.
1:Experimental Design and Method Selection:
The study employs crystalline silicon (c-Si) metasurfaces with high-contrast grating (HCG) unit cells for phase control. The design is validated using finite difference time domain (FDTD) simulations.
2:Sample Selection and Data Sources:
A thin film c-Si is transferred from an SOI wafer onto a quartz substrate. The HCG is fabricated by electron beam lithography (EBL).
3:List of Experimental Equipment and Materials:
Equipment includes EBL (Raith Vistec EBPG-5000 plus ES), inductively coupled plasma (ICP, Oxford Instruments), and a solid-state laser emitting at 532 nm. Materials include ZEP520A resist, aluminum, and NOA61 adhesive.
4:Experimental Procedures and Operational Workflow:
The process involves transferring c-Si onto quartz, patterning with EBL, etching with ICP, and characterizing the deflective metasurface with a laser setup.
5:Data Analysis Methods:
The deflection efficiency and angle are measured and compared with theoretical predictions.
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