Wide-temperature-range athermalization for MWIR hybrid refractive/diffractive optical system

A hybrid refractive/diffractive Petzval lens has been designed. Its working wavelength range is 3.2-4.5 m, full field of view is 8.42, efficient focal length is 95 mm and back focal length is 60.5 mm. The Petzval lens consists of four lenses, including two aspheric surfaces and a diffractive surface, which make the Petzval lens compact and light. Its modulation transfer function is above 0.7 in the temperature range from -80 to 160 ℃. The Petzval lens is compatible with the uncooled staring focal plane array which has a format of 320240 and the pixel pitch of 35 m.