Design of an all-reflective active zoom system.

Based on active optics, the zoom system design can no longer be confined to traditional methods of changing the distances between optical components for variable focal lengths. An all-reflective active zoom system with three mirrors is designed. The primary and third aspheric mirrors act as deformable mirrors to realize the transition among the different focal lengths by the curvature radius variation, while the second aspheric mirror is static. According to the third-order aberration theory and dimension calculations of the optical system requirements with the constraint limitations, the system's initial construction parameters can be achieved. This all-reflective active zoom system can realize zoom ratio is 3, focal length between 5 and 15 mm, field-of-view of 10–27.8°, and wide working wavelength from the visible to infrared. [ABSTRACT FROM AUTHOR]