英语翻译First there is an optical gain medium that amplifies the

First there is an optical gain medium that amplifies the light via stimulated emission and second an optical feedback structure that repeatedly passes a resonant light field through the gain medium to establish a very intense,coherent optical field inside the laser.首先,有一种光增益介质,该介质能通过受激发射放大光,其次,有一个反馈结构,此结构可以经过增益介质反复通过谐振光场,从而在激光器内建立起很强烈的、相干的光场.
A second simple configuration for an optical cavity is an optical ring resonator,in which the light circulates as a travelling wave around a closed path defined by three or more mirrors
光谐振腔的第二种简单的结构是一种环形谐振腔,光在腔内利用三个或更多个反射镜作为行波绕一个闭合的通道循环.