On the preparation of high reflectance aspherical mirrors by thin-film deposition

NCU Institutional Repository > 理學院 > 光電科學研究所 > 期刊論文 > Item 987654321/28217

jsp.display-item.identifier=請使用永久網址來引用或連結此文件: http://ir.lib.ncu.edu.tw/handle/987654321/28217

题名:	On the preparation of high reflectance aspherical mirrors by thin-film deposition
作者:	Jaing,CC;Lee,CC
贡献者:	光電科學研究所
日期:	1996
上传时间:	2010-06-29 19:44:10 (UTC+8)
出版者:	中央大學
摘要:	One of the problems of making aspherical mirrors by thin-film deposition of aluminium is the low reflectance of the films. Such a low reflectance of the films is due to the fact that the aluminum film is too thick and makes the surface rough, resulting in scattering of light [1-5]. Another problem is that the reflectance of an aspherical mirror is not the same at different zones, because the thickness distribution of an aluminium film is not uniform. For example, for a desired paraboloid with a vertex radius, R, and a starting spherical substrate with a curvature radius, R', and a maximum radius, S-0, the required film thickness distribution, D(S), is S-2(S-0(2)-S-2)/8R'(3), where S is the radius [5]. The relationship between R and R' is R = (4R'(3))/(4R'(2) + S-0(2)). Differentiating D with respect to S, we then find that the largest film thickness is S-0(4)/32R'(3) at S = (1/2)S-1/2(0). Assuming that R = 500 mm and S-0 = 50 mm, the thickness of the film is 1.661 mu m, which is too thick to have such high reflectance as a thin aluminium film does. To deposit thick films and still maintain good optical quality is state of the art. Dobrowolski and Weinstein used zinc sulfide to make aspherical lenses that exhibited no peeling or cracking [3, 4]. A zinc sulfide-thorium fluoride mixture evaporation source was suggested to make aspherical mirrors by Kurdock and Austin [6]. In this paper we show the results obtained when an Al2O3 layer is deposited to form an aspherical surface, followed by deposition of a thin layer of aluminium.
關聯:	OPTICAL AND QUANTUM ELECTRONICS
显示于类别:	[光電科學研究所] 期刊論文

文件中的档案:

档案	描述	大小	格式	浏览次数
index.html		0Kb	HTML	500	检视/开启

在NCUIR中所有的数据项都受到原著作权保护.

社群 sharing

数据加载中.....