external target meaning in English

外靶

When a portion of light emitted from a laser source is reflected or scattered back into the laser cavity by an external target , the reflected light will mix with the light inside the cavity , causing a modulation of the laser output power
激光自混合效应是指激光器输出的光被外部物体反射或散射后，其中一部分光又反馈回激光器的谐振腔，反馈光携带了外部物体的信息。与腔内光相混合后，会调制激光器的输出，称为自混合效应。
This phenomenon is called as self - mixing effect , in which the reflected light carries some information of the external target . the self - mixing effect comes from the optical feedback effect . people always tried to eliminate the optical feedback effect previously
激光的自混合效应来源于激光器的外部光反馈效应，以前人们总是设法消除光反馈的影响，后来逐渐的由消除光反馈的不利影响到主动利用光反馈效应检测物理量，从而形成了一门新的技术。