The green laser is a semi-reflection mirror. It combines the light beams of two (or more) wavelength into one direction by transmission and reflection.

合束镜是一种半透反射镜，它将两种（或多种）波长的光线分别通过透射和反射的方法合成到一条光路上。

youdao

In a beam transmission system of a CO2 laser, the reflection mirror can be used as back-view mirror or foldable reflection mirror in the laser cavity, while as a light bender outside the cavity.

在CO2激光器的光束传输系统中，反射镜在激光管腔内被用作尾镜和折叠式反射镜，而在腔外则充当了弯光器的角色。

youdao

youdao

She turned away from the reflection in the mirror, determined he not see her fear.

NPR: Excerpt: 'Killer Weekend'

Guyotat looks at her reflection in the mirror and looks at the back of her neck.

NEWYORKER: Labyrinth

But he could see, out of the corner of his eye, his horrid reflection in the mirror behind the bar.

NEWYORKER: Another Manhattan