Q Switching

Q-switching is a technique used to produce a high output pulse. It is accomplished by using a device to prevent the reflection of photons back and forth  in the active medium. This produces a  higher population inversion in the  metastable state. Then suddenly the optical cavity is opened to permit a large fraction of stored energy to be emitted in the form of very intense pulse of laser radiation. Q-switched lasers produce pulses of  10 to 250 nanoseconds.

Q-switching is also known as Q-spoiling.

As the quality factor Q of a laser cavity shows the ability of the cavity to store energy, thus, high Q means that high energy can be stored  in the cavity and a low Q means that the cavity will rapidly dissipate its energy. As the technique of Q-switching involves switching the optical cavity quality factor Q from a low to a high value, therefore, it is known as Q-switching.

Techniques of the Q-Switching : Continue reading “Q Switching”