A dual-band step-zoom infrared optical system with four lenses is designed on the basis of the special properties of Harmonic Diffractive Element(HDE) and the zoom theory.

• 基于变焦系统的基本原理,利用谐衍射透镜的相关特性并结合中波红外和长波红外的特点,设计了仅含有4片透镜的红外双波段双焦光学系统。