Passively athermalised hybrid Petzval objective for high resolution MWIR detector arrays
Abstract:To meet the requirement of extensive temperature adaptability of infrared optical systems, diffractive optics is applied to a high resolution Petzval objective in the 3–5 μm waveband and a hybrid Petzval objective, which is passively athermalised over the temperature range –20 °C to +50 °C, is designed. Only two materials Si and Ge are used. The theoretical polychromatic MTF is above 0.80 at 20 cycles/mm and near diffraction-limited; the geometrical spot diameter is controlled to within 20 μm over the range of temperature. The lens is compatible with a latest generation Middle Wave Infrared (MWIR) staring array imager with the pixel size of 25 μm. The manufacturing issues related to the diffractive surface are also described.
Document Type: Research Article
Affiliations: Institute of Modern Optics, Nankai University, The Key Laboratory of Opto-electronic Information Science and Technology, Ministry of Education, Tianjin, 300071, China
Publication date: July 1, 2004