SWIR objective design using Seidel aberration theory

Tezin Türü: Yüksek Lisans

Tezin Yürütüldüğü Kurum: Orta Doğu Teknik Üniversitesi, Fen Edebiyat Fakültesi, Fizik Bölümü, Türkiye

Tezin Onay Tarihi: 2016

Tezin Dili: İngilizce

Öğrenci: SERHAT HASAN ASLAN

Eş Danışman: Onur Keskin

Danışman: Sinan Kaan Yerli

Özet:

Optical systems are used for increasing the situational awareness and Intelligence, Surveillance and Reconnaissance (ISR) capabilities for military purposes. MWIR (Midwave infrared) and LWIR (Long wave infrared) waveband informations are the first two wavebands information in the atmospheric transmission window that are harnessed in military night vision optical systems. Another candidate of these operable wavebands is the SWIR (Shortwave infrared). Shortwave infrared (SWIR) imaging is an extension of Near Infrared (NIR) and visible (VIS) imaging applications and SWIR waveband is defined between 0.9-1.7 m for InGaAs SWIR detectors. SWIR radiation in the atmosphere is based on atmospheric night glow which is a phenomenon created by the hydroxyl ion emissions in the upper atmosphere. There are benefits of SWIR such as fog and haze penetration, cloud and smoke penetration over NIR, VIS, MWIR and LWIR bands. A SWIR objective optical design process is outlined in this thesis using Seidel aberration theory or namely third order aberration theory starting from the thin lens predesign. First, typical optical layouts are discussed with respect to certain optical specifications. Using paraxial optical relations, optical design is finalized using ideal lenses. Aberrations in an optical design are defined in terms of wavefront expansions in order to correct aberrations methodologically. Third order components of wavefront expansion are considered initially and corrected by the thin lens parameters of the paraxial design. Ideal thin lenses are realized and thickened by using the thin lens parameters which are calculated in third order analysis. After thirdorder components are corrected perfectly, fifth order aberrations are balanced with third order aberrations using numerical optimization routines. Finally, tolerancing procedure is discussed and as built imaging quality of the optical design is calculated by tolerancing procedure.