Under astigmatism even narrow parallel light beams will not combine into one point . 有象散存在時甚至很窄的平行光束都不能會聚在一點。
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 摘要介紹一種超小型光纖導光干涉儀,它利用光纖和自聚焦透鏡的耦合來形成平行光路,利用半反和全反光學膜片分光。