Under astigmatism even narrow parallel light beams will not combine into one point . 有象散存在时甚至很窄的平行光束都不能会聚在一点。
A type of small - sized interferometer is reported , which makes use of the coupling of optical fiber and gradient index lens ( grin ) to form parallel light beams 摘要介绍一种超小型光纤导光干涉仪,它利用光纤和自聚焦透镜的耦合来形成平行光路,利用半反和全反光学膜片分光。