無偏振選擇的超寬頻帶消色差超穎透鏡

An ultra-broadband achromatic metalens without polarization selection

呂岱融(Dai-Rong Lu)

指導教授 ： 管傑雄

共同指導教授 ： 蘇文生(Vin-Cent Su)

國立臺灣大學/電機資訊學院/電子工程學研究所/碩士(2019年)

https://doi.org/10.6342/NTU201903314

摘要

寬頻超穎透鏡有別於傳統相機鏡頭，能在小尺寸下達到消色差的效果，這使得許多光學元件在體積及重量上能大大縮小。因此近幾年來各個研究團隊不斷致力於研發寬頻超穎透鏡，但目前主流的設計方法並無法達成無偏振選擇特性，且透鏡效率值較低，操作頻寬過窄，使得其在實際應用上遇到了瓶頸。
本篇論文將探討超穎透鏡的發展，並在設計、模擬、製程、量測上做詳細的介紹。我們選用六角環柱之氮化鎵材料進行單元結構設計，最終完成在各種線偏振角度入射下均能聚焦的無偏振選擇超穎透鏡，且其在波長633奈米處效率高達90%，操作頻寬由整個可見光區至近紅外光，並且能在量測上達到白光聚焦的效果。在文末也提及使用多週期合併之設計方法，預期能擴大設計區域並獲取更大的數值孔徑。總體而言，超穎透鏡極具發展潛力，預期在未來將會取代許多傳統光學透鏡。

關鍵字

超穎透鏡 ； 消色差 ； 氮化鎵

並列摘要

Broadband meta-lenses are different from traditional camera lenses.They can achieve achromatic effects in tiny units and make many optical components much smaller in size and weight. Therefore, in recent years, various research teams have been working hard to develop broadband meta-lenses. However, current design methods can not achieve non-polarization selective characteristics, the efficiency of the meta-lenses is low, and the operation bandwidth is too narrow. These problems make it encounter bottlenecks in practical applications.
This paper explores the development of meta-lenses and provides a detailed introduction to design, simulation, process, and measurement. We chose gallium nitride material and hexagonal ring-column for cell structure design and finally completed the non-polarization-selective meta-lens that could focus at various angles of linear polarization. Its efficiency was about 90% at a wavelength of 633 nm. The operating bandwidth was from the entire visible region to the near-infrared light. The white light focusing could also be achieved on the measurement. At the end of the paper, We propose the design method of multi-cycle meta-lens and expect to expand the design area and obtain a larger numerical aperture. In general, meta-lenses have great potential to replace many traditional optical lenses in the future.

並列關鍵字

metalens ； achromatic ； Gallium nitride

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