Coherent, Inc.

Gerald M Mitchell

J Michael Yarborough

Edward D Reed, Jr

R Rox Anderson

Michael Hmelar

Kevin P Connors

Greg J Spooner

George Marcellino

Kenneth J Bossie

David Trost

James L Hobart

Thomas W McCurnin

Dennis G Fischer

Nubar Sahag Manoukian

Bernard J Couillaud

Michael L Krupp

Enrique M Celaya

Richard G Caro

A medical laser system is disclosed for ablating biological material. The system includes an Erbium:YAG gain medium capable of generating a pulsed output having a wavelength of 2.9 microns. The laser is optimized to generate a pulsed output having a repetition rate of at least 50 hertz and preferably at least 100 hertz. The output is delivered to the target tissue via an optical fiber. Preferably, a suction source is provided to aspirate the tissue as it is being ablated. The erbium laser system provides accurate ablation with minimal damage to surrounding tissue.

High repetition rate erbium:YAG laser for tissue ablation

An apparatus and method is disclosed for treating vascular lesions. In the preferred embodiment, an intracavity, frequency doubled Nd:YAG laser is used to generate output pulses having a duration of 0.5 to 10.0 milliseconds. This laser output is used to irradiate the lesions. The laser energy is absorbed in the blood of the vein, causing it to coagulate and collapse. The long pulse duration helps to minimize bleeding while controlling thermal damage to surrounding tissue.

Method and apparatus for treating vascular lesions

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 medical laser system is disclosed for ablating biological material. The system includes an Erbium:YAG gain medium capable of generating a pulsed output having a wavelength of 2.9 microns. The laser is optimized to generate a pulsed output having a repetition rate of at least 50 hertz and preferably at least 100 hertz. The output is delivered to the target tissue via an optical fiber. Preferably, a suction source is provided to aspirate the tissue as it is being ablated. The erbium laser system provides accurate ablation with minimal damage to surrounding tissue

High repetition rate Eribum-YAG laser for tissue ablation

High repetition rate erbium; YAG laser for tissue ablation

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

A method and apparatus for minimizing damage to an optical fiber used as part of a laser radiation delivery system are disclosed. The apparatus includes the use of a spacer positioned adjacent the tip of the fiber to minimize the impact on the fiber tip of debris and vapor generated by exposure of a tissue target to high energy radiation. The end of the apparatus is configured to vent debris and vapor from the end of the tip to reduce damage. The fiber tip may also be annealed to enhance its resistance to damage. The method includes the step of spacing the fiber tip at a predetermined distance from the tissue target during exposure of the tissue target to laser radiation, and may include venting the debris created away from the fiber end. The method may further include the step of providing an annealed fiber tip.

Contact laser delivery probe

A wedge mirror is disclosed for suppressing the high gain wavelengths in a laser. The mirror is provided with a pair of opposed surfaces lying in nonparallel planes. Each of the surfaces is provided with a wavelength selective coating. The coating on the surface of the mirror facing the gain medium is highly reflective of the high gain wavelength and highly transmissive of the low gain wavelength. This surface is oriented so that the light from the high gain wavelength is reflected out of the cavity. The outer surface of the mirror is highly transmissive of the high gain wavelength and highly reflective of the low gain wavelength. The combination of the wavelength selective coatings and the wedge configuration allows the high gain wavelength to be suppressed while the low gain wavelength oscillates. The subject mirror is particularly suited for suppressing the 1.06 and 1.33 micron wavelengths in Nd:YAG while allowing the 1.44 micron wavelength to lase.

Cavity mirror for suppressing high gain laser wavelengths

A method and device for preventing premature optics burn-out in a laser having a solid gain medium is provided. The invention involves preheating the gain medium by supplying power at a level which is sufficient to set up a thermal lens, yet insufficient to cause substantial production of laser light. In one approach, a simmer routine is overlaid on a ramp routine, so that the power supplied to the gain medium is gradually increased during the warm-up period.

Method and device for preconditioning a laser having a solid state gain

The subject invention relates to method of suppressing one of the counterpropagating intracavity pulses generated in a dye laser synchronously pumped by the output of a mode locked Q-switched pump laser. The method includes extracting a portion of one of the pulses generated in the cavity such that the other pulse experiences a greater effective gain. The pulse with the highest effective gain will dominate the other pulse and at the steady state only one pulse will exist in the cavity. In the preferred embodiment, a double pass acousto-optic cell is used to extract the both the unwanted pulse and, at a later time, the high energy, useful pulse. In this case, maximum efficiency is achieved by placing the dye cell at one of a number of well defined locations within the optical cavity.

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Tucson, AZ, United States of America

Gerald M Mitchell