传统的空间望远镜是根据分辨率衍射极限公式,通过增大系统的通光口径来提高分辨率的,但这样系统的体积和重量相应增大,增加了空间运载的难度。负折射率材料(Negative Index Materials,NIMs)的出现,为高分辨率空间望远镜的发展提供了新的思路。NIMs对含有物体精细结构信息但在真空中随距离指数衰减传播的渐失场有增益放大作用,从而使渐失场能够参与成像,实现光学系统传统分辨率衍射极限的突破。本文介绍了NIMs的研究历史,分析了由负折射产生的负群速度、逆Doppler频移、反常Cerenkov辐射、负折射等各种效应,重点讨论了采用NIMs实现望远系统传统分辨率突破的内涵和意义以及今后研究工作的重点。

Traditional space telescopes can improve the resolution by increasing the system aperture in accordance with the diffraction limit formula of resolution. However,as the corresponding volume and weight of the system are increased,it is difficult to be carried on a spacecraft. The emergence of Negative Index Materials(NIMs) provides a new way for the development of high-resolution space telescopes. This paper introduces the history and research of NIMs and outlines their special properties,such as negative group velocity,inverse Doppler effect,abnormal Cerenkov radiation and negative refraction effect,then it discusses the functions of NIMs and why the NIMs can be used to improve the telescope resolution. It points out that NIMs amplify evanescent fields containing information of the fine structure of objects and decaying exponentially in a vacuum with distance,so that the evanescent fields can participate in imaging. These properties of the NIMs make the resolution of an optical system better than the traditional diffraction limit.