Coherent, Inc.

Kenneth J Bossie

J Michael Yarborough

Gerald M Mitchell

David Trost

James L Hobart

Edward D Reed, Jr

Kevin P Connors

Thomas W McCurnin

A liquid circulation system for cooling a laser head is disclosed. The circulation system comprises a main storage tank for holding a cooling liquid and a pump for circulating the liquid from the tank through the laser head and back into the tank. The cooling system includes a heat exchanger for cooling the liquid. The heat exchanger includes liquid carrying coils and an impeller fan rotatable about an axis. The fan being located adjacent the coils for drawing air across the coils in an axial direction with respect to the fan and for expelling the air radially with respect to the fan.

Liquid circulation system for cooling a laser head

A pulsed solid state laser system is disclosed which utilizes a plurality of individual laser rods which are sequentially pumped and whose beans are combined into a single interleaved output bean. The individual laser rods are pumped at an average power level which is below that for maximum output power from each rod, thereby obviating the need for refrigeration cooling. A compact optical system is disclosed which permits a constant beam size even at different pump levels and other advantages. A compact cooling system is also disclosed.

Solid state laser with interleaved output

An optically-pumped solid state laser system having separate subsystems for cooling its gain medium and optical pumping assembly. The invention permits the operating temperatures of the gain medium and optical pumping assembly to be independently controlled, and permits a substantial increase in cooling efficiency as a result of independent control of coolant flow rates in the two cooling subsystems. In a class of preferred embodiments, the gain medium cooling subsystem includes a first channel through which coolant flows with relatively high flow rate and relatively low temperature (to maintain the gain medium at a desired low operating temperature), and the other cooling subsystem includes a second channel through which coolant flows with a relatively low flow rate and relatively high temperature. In one embodiment, the gain medium is a Holmium:YAG rod, and a Cerium doped glass tube surrounds the rod. Three to four gallons per minute of coolant flows through the tube to maintain the rod at an operating temperature in the range from about + 10 to - 15 degrees Celsius. The optical pumping assembly includes a set of flash lamps, and a Cerium doped glass tube surrounds each lamp. A total of no more than two gallons per minute of coolant flows through the tubes around the lamps, to maintain the lamps at a relatively high (but controlled) temperature.

Solid state laser with dual cooling loops

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Tucson, AZ, United States of America

Kenneth J Bossie