Rami Arieli: "The Laser Adventure"

Rami Arieli: "The Laser Adventure" Section 6.2.2 page 2

Energy Level Diagram of Nd-YAG laser
The energy level diagram of a Nd-YAG laser can be seen in figure 6.15.

Figure 6.15: Energy Level Diagram of a Nd-YAG Laser

As can be seen from the energy level diagram, Nd lasers are four level lasers.

Nd ions have two absorption band, and excitation is done by optical pumping, either by flash lamps for pulsed lasers, or by arc lamps for continuous wave lasers.

From these excited energy levels, the Nd ions are transferring into the upper laser level by a non radiative transition.

The stimulated emission is from the upper laser level to the lower laser level, and the wavelengths of the emitted photons are around 1.06 [mm].

From the lower laser level, a non-radiative transition to the ground level.