Patent ID: 7502396

Claim:
A solid-state laser apparatus adapted to cool a solid-state laser medium with a coolant, the apparatus comprising: a main pipe for circulating the coolant through the solid-state laser medium; cooling means, provided in the main pipe, for cooling the coolant; a bypass pipe connected in parallel to at least a part of the main pipe; neutralizing means, provided in the bypass pipe, for weakening an acidity or alkalinity of the coolant; flow regulating means, provided upstream of the neutralizing means in the bypass pipe, for regulating a flow rate of the coolant flowing into the bypass pipe; and control means for controlling the flow regulating means such as to increase the flow rate of the coolant flowing into the bypass pipe when the coolant is acidic or alkaline, wherein the main pipe is provided with a pump for circulating the coolant, wherein the bypass pipe is connected in parallel to at least a part of the main pipe between the solid-state laser medium and an intake of the pump, and wherein an upstream end and a downstream end of the bypass pipe are connected to the main pipe between the solid-state laser medium and an intake of the pump.