Gain-Switched Solid-State-Laser Pumped by High Brightness Laser Diodes

Abstract

Solid state pulsed laser (such as Nd:YAG) with pulse width in the 10-100 ns range are well known Major technique, the Q-switching technique (switching of the internal cavity losses) delivers high peak powers. The long lifetime of the upper laser level (100-200 µs) leads to high level energy stored, but limits the pulse repetition frequency. Gain-switching (switching of the pump power) is the competing technique. The non insertion of a switching cell in the cavity leads to reduced losses, shorter and rugged lasers. But, as the gain-switching deals with the laser dynamic, the stored energy is lower than in Q-switching. Actually, achieving good efficiency in gain-switching mode needs high brightness pumping source. As the pump pulse duration (about 1 µs in our case) is small by comparison with Q-switching, gain-switching allows higher frequency (1-100 kHz) [1].