A high efficiency, high power, solid state laser

Yttrium aluminum garnet (Y3Al5O12) doped with trivalent neodymium as an active ion, and trivalent chromium as an activator or energy transfer agent, has been operated as a continuous room temperature laser at the ten watt output level with 0.33% overall efficiency when pumped with a high pressure mercury lamp. The operating characteristics of this laser are strongly influenced by the energy transfer rate from the Cr³⁺to the Nd³⁺. The typical transfer rate of 1 ms gives rise to a repetitive spiking output when the laser is operated at high power levels, the spikes being typically of 0.6 µs duration and 160 watts peak power. The optical design and operation of this laser will be discussed along with considerations as to the efficiency and output power that could be achieved with further optimization of the system parameters.