CASE STUDY
The ruby laser is one of the solid lasers. It consists of a ruby rod. This is made of chromium doped ruby material. At the opposite ends of this rod there are two silver polished mirrors. Whose one is fully polished and other is partially polished. A spring is attached to the rod with fully polished end for adjustment of wave length of the laser light. Around the ruby rod a flash light is kept for the pump input. The whole assembly is kept in the glass tube. Around the neck of the glass tube the R.F source and switching control is designed in order to switch on and off the flash light for desired intervals.
When we switch on the circuit the R.F operates. As a result the flash of light is obtained around the ruby rod. This flash causes the electrons within ruby rod to move from lower energy band towards higher energy band. The population inversion takes place at high energy band and electrons starts back to travel towards the lower energy band. During this movement the electron emits the laser light. This emitted light travels between the two mirrors where cross reflection takes place of this light. The stimulated laser light now escapes from partially polished mirror in shape of laser beam. The spring attached with the fully polished mirror is used to adjust the wave length equal to λ/2 of laser light for optimum laser beam. The switching control of the R.F source is used to switch on and off the flash light so that excessive heat should not be generated due to very high frequency of the movement of the electron.