Micro-Optical Line Generator Metalens for a Visible Wavelength Based on Octagonal Nanopillars Made of Single-Crystalline Silicon
Micro-Optical Line Generator Metalens for a Visible Wavelength Based on Octagonal Nanopillars Made of Single-Crystalline Silicon
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基于单晶硅八角形纳米柱的可见光波长微光学线发生器Metalens
DOI：
10.1109/jsen.2022.3186060
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发表时间：
2022
影响因子：
4.3
通讯作者：
Iwami Kentaro
中科院分区：
文献类型：
--
作者：
Ikezawa Satoshi;Yamada Ryota;Takaki Kosuke;Ogawa Chikara;Iwami Kentaro
传统上，与包括二氧化钛、氮化硅和氮化镓的其他无损材料相比，硅不太经常被选择作为可见波段中的电介质超颖表面的材料。原因是其相对较高的消光系数和由此产生的低透射率。这项研究表明，由单晶硅制成的精确设计的纳米柱可以令人满意地用于超颖表面，甚至在可见光波段。为了验证硅纳米柱在可见光波段的透镜性能，设计了四个线聚焦超颖表面透镜。此外，字符投影和可变形状的电子束光刻模式的组合操作，以评估批量生产率和精度之间的兼容性。我们成功地获得了由单晶硅纳米柱组成的高效线聚焦超颖表面透镜。超颖表面透镜在532 nm波长下的参数如下：透镜厚度，300 nm;焦距，3.91 mm;正方形孔径，2 mm;数值孔径，0.25;测量的透射率，38.4%至46.8%;以及测量的焦点处的束斑宽度（半峰全宽，FWHM）。在这项研究中获得的结果显示了一个有前途的使用硅超颖表面的光学传感器应用在可见光波段。
Conventionally, silicon is less often selected as the material of dielectric metasurfaces in the visible band than other lossless materials, including titanium dioxide, silicon nitride, and gallium nitride. The reason is its relatively high extinction coefficient and resulting low transmittance. This study demonstrated that accurately designed nanopillars made of single-crystal silicon could be used satisfactorily on a metasurface, even in the visible band. Four line-focusing metasurface lenses were designed to verify the lens performance effectiveness of silicon nanopillars in the visible band. In addition, a combination of the character projection and the variable-shaped beam modes in the electron beam lithography was operated to evaluate the compatibility between mass productivity and accuracy. We successfully obtained a highly efficient line-focusing metasurface lens composed of single crystalline silicon nanopillars. The parameters of the metasurface lens at a wavelength of 532 nm were as follows: lens thickness, 300 nm; focal length, 3.91 mm; square aperture, 2 mm; numerical aperture, 0.25; measured transmittance, 38.4% to 46.8%; and measured beam spot width,(full width at half maximum, FWHM) at the focal point. The results obtained in this study show a promising use of silicon metasurface for optical sensor applications in the visible band.