Dual-band and wide-band lenses covering both the MWIR and LWIR spectral bands are increasingly needed as dualband MWIR/LWIR detectors have become prevalent and broadband applications have expanded. Currently in dual-band /wide-band applications, the use of more than three elements per lens group and the use of chalcogenide glass is common. This results in expensive systems. Also, many chalcogenides are available only in small diameters, which is a problem for large aperture broadband lenses. In this paper an investigation of cost-effective designs for dual-band MWIR/LWIR lens using only widely available IR materials, specifically Ge, ZnSe and ZnS were performed. An athermalized dual-band MWIR/LWIR using these three materials is presented. The performance analysis of this lens shows that this design form with these three common IR materials works well in certain applications. The required large size blanks of these materials can be easily obtained. Traditional chromatic aberration correction without diffraction for either wide-band or dual-band application was employed. In addition, the methods of harmonic diffraction for dual-band applications, especially with one narrow band, were used for two different presented designs.

Date Published: 12 October 2016
PDF: 10 pages
Proc. SPIE 9947, Current Developments in Lens Design and Optical Engineering XVII, 994708 (12 October 2016); doi: 10.1117/12.2238086

Published in SPIE Proceedings Vol. 9947:
Current Developments in Lens Design and Optical Engineering XVII
R. Barry Johnson; Virendra N. Mahajan; Simon Thibault, Editor(s)