定义：
注入锁定到另一个激光器上的激光器。

从属激光器产生的光频率是由一个外在的主激光器（种子激光器）通过注入锁定来控制的。通常来讲，种子激光器是一个低噪声的单频激光器，而从属激光器则是一个高功率激光器。
通常采用电子伺服系统使从属激光器的谐振腔模频率与主激光器足够接近来实现频率锁定。 
当主激光器被关掉或者移走，高功率激光器甚至不会辐射单频率，或者至少具有很高的强度和相位噪声。
相比于直接采用高功率激光器得到低噪声性能，注入锁定更有利于得到很好的噪声特性。一个主激光器可以同时驱动多个从属激光器

Definition: a laser which is injection-locked to another laser

More general terms: lasers

Opposite term: master laser

A slave laser is a laser which emits on an optical frequency which is dictated by an external master laser (seed laser) via injection locking. Typically, the seed laser is a low-noise single-frequency laser, and the slave laser is a high-power laser. An electronic servo system is usually used to keep the frequency of a resonator mode of the slave laser close enough to the frequency of the master laser to allow for frequency locking.

With the master laser removed or turned off, the high-power laser would typically not even emit on a single frequency, or at least with a much higher intensity and phase noise. Injection locking makes it easier to achieve good noise properties, comparing with the attempt of directly obtaining low-noise performance of a high-power laser. It is also possible to drive multiple slave lasers with a single master laser.

A possible alternative would be to simply use an optical amplifier, but particularly with high-power amplifiers it is often difficult to achieve as much gain as with injection looking. Also, the noise properties can be substantially better with injection looking.