18 June 2013 New multiband IR imaging optics
Author Affiliations +
We report new multispectral materials that transmit from 0.9 to < 12 µm in wavelength. These materials fill up the glass map for multispectral optics and vary in refractive index from 2.38 to 3.17. They show a large spread in dispersion (Abbe number) and offer some unique solutions for multispectral optics designs. One of the glasses developed is a very good candidate to replace Ge, as it has a combination of excellent properties, including high Abbe number in the LWIR, high index of 3.2, 60% lower dn/dT, and better thermal stability at working temperatures. Our results also provide a wider selection of optical materials to enable simpler achromat designs. For example, we have developed other glasses that have relatively high Abbe number in both the MWIR and LWIR regions, while our MILTRAN ceramic has low Abbe number in both regions. This makes for a very good combination of glasses and MILTRAN ceramic (analogous to crown and flint glasses in the visible) for MWIR + LWIR dual band imaging. We have designed preliminary optics for one such imager with f/2.5, 51 mm focal length and 22 degrees FOV using a spaced doublet of NRL's glass and MILTRAN ceramic. NRL's approach reduces the number of elements, weight, complexity and cost compared with the approach using traditional optics. Another important advantage of using NRL glasses in optics design is their negative or very low positive dn/dT, that makes it easier to athermalize the optical system.
© (2013) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Shyam Bayya, Shyam Bayya, Jasbinder Sanghera, Jasbinder Sanghera, Woohong Kim, Woohong Kim, Daniel Gibson, Daniel Gibson, Erin Fleet, Erin Fleet, Brandon Shaw, Brandon Shaw, Michael Hunt, Michael Hunt, Ishwar Aggarwal, Ishwar Aggarwal, "New multiband IR imaging optics", Proc. SPIE 8704, Infrared Technology and Applications XXXIX, 870428 (18 June 2013); doi: 10.1117/12.2016332; https://doi.org/10.1117/12.2016332

Back to Top