可見光寬頻寬能隙超穎透鏡

Abstract

超穎透鏡具有體積小且重量輕的優點，在傳統光學元件中，若要達到消色差或是其他光學效果，必須透過多個不同鏡組來實現，這不僅會增加重量，而且現在的光學透鏡的材料大多都是玻璃，這會造成另外一項缺點就是容易損毀。穿透式超穎透鏡利用次波長超穎表面組成，其可控制之波段為可見光波段。 本論文之超穎透鏡選用氮化鎵當作介電材料，利用電感耦合式電漿乾蝕刻蝕刻氮化鎵深度800奈米。在乾蝕刻過程中遇到時側壁傾斜的問題，造成其光學表現不佳，本論文將對於蝕刻氮化鎵之側壁垂直度進行探討。 最後以雙面拋光的藍寶石做為基板，且以氮化鎵做為介電質矩形結構材料，製作而成的可見光波段穿透式超穎透鏡有三種不同的焦距以及NA值，所製成之最成功的超穎透鏡有良好的消色差效果，以及其平均效率可以達到50%。 且透過1951 USAF分辨力測試圖，測量其解析度，其中最成功的樣品可成像至長度2.19微米大小之影像，並利用投影實際照片確認此超穎透鏡之色彩表現。 關鍵詞:超穎透鏡、消色差、氮化鎵、電感耦合式電漿乾蝕刻、電子束微影

Metalenses have the advantages of small size and light weight, in the traditional optical components, to achieve achromatic or other optical effects, must be achieved through a number of different sets of mirrors, which will not only increase the weight, and now most of the optical lenses are made of glass. It is easy to break. The penetrating metalens is composed of the subwavelength metasurface, and its controllable band is visible optical band. In this thesis, gallium nitride is selected as dielectric material, and the depth of gallium nitride is etched by inductively coupled plasma reactive-ion etching of 800 nm. In the process of dry etching, the side wall inclination is encountered, which results in poor optical performance, and the side wall verticality of the etching gallium nitride is discussed in this thesis. Finally, the two-sided polished sapphire as the base plate, with gallium nitride as dielectric rectangular structure material, the visible optical band penetrating metalens has three different focal lengths and NA values, the most successful metalens has good achromatic effect, and its average efficiency can reach 50%. The resolution of the 1951 USAF resolution target is measured, and the most successful samples can be imaged to a length of 2.19 microns, and the color representation of this super lens is confirmed by the actual projection of the image. Keyword:metalense、achromatic、GaN、inductively coupled plasma reactive-ion etching、E-beam lithography