Abstract: A laser system employing one or more mirror sets having substantially astigmatism-free focusing power sufficient to maintain a desired laser beam diameter, for example, to compensate for thermally-induced distributed lensing. In one class of preferred embodiments, the invention is a high power gas laser system having a folded optical cavity with a periodic intracavity refocusing means to compensate for distributed negative thermal lensing in the hot plasma that comprises the active medium, and thus maintain a substantially constant beam diameter throughout the optical cavity. The periodic intracavity refocusing means preferably includes a corner mirror set (including at least one curved mirror and at least one other mirror) at each corner of the folded optical cavity. In one preferred embodiment, each corner mirror set is a mirror pair including a spherical mirror and cylindrical mirror.

Abstract: A laser system employing one or more mirror sets having substantially astigmatism-free focusing power sufficient to maintain a desired laser beam diameter, for example, to compensate for thermally-induced distributed lensing. In one class of preferred embodiments, the invention is a high power gas laser system having a folded optical cavity with a periodic intracavity refocusing means to compensate for distributed negative thermal lensing in the hot plasma that comprises the active medium, and thus maintain a substantially constant beam diameter throughout the optical cavity. The periodic intracavity refocusing means preferably includes a corner mirror set (including at least one curved mirror and at least one other mirror) at each corner of the folded optical cavity. In one preferred embodiment, each corner mirror set is a mirror pair including a spherical mirror and cylindrical mirror.

Abstract: An improved gas laser is disclosed. The laser has a support tube to support and to maintain the alignment of the optical resonator structure. The gas lasing medium is used within the support tube to maintain the tube at a substantially constant temperature above the ambient. Furthermore, an active temperature controller is disclosed. The temperature controller maintains the gas lasing medium in the support tube at a substantially constant temperature. An active pressure controller is also disclosed. The active pressure controller uses a pressure sensor, an electronic processor, and a motor-driven needle valve to maintain the pressure of the gas lasing medium in the laser within the desired operating pressure range. The laser can also be switched in operation from a continuous mode to a pulsing mode. An active power control system is disclosed wherein the power output of the laser, through an active feedback loop is maintained at the desired level.

Abstract: An improved gas laser is disclosed. The laser has a support tube to support and to maintain the alignment of the optical resonator structure. The gas lasing medium is used within the support tube to maintain the tube at a substantially constant temperature above the ambient. Furthermore, an active temperature controller is disclosed. The temperature controller maintains the gas lasing medium in the support tube at a substantially constant temperature. An active pressure controller is also disclosed. The active pressure controller uses a pressure sensor, an electronic processor, and a motor-driven needle valve to maintain the pressure of the gas lasing medium in the laser within the desired operating pressure range. The laser can also be switched in operation from a continuous mode to a pulsing mode. An active power control system is disclosed wherein the power output of the laser, through an active feedback loop is maintained at the desired level.

Abstract: An improved gas laser is disclosed. The laser has a support tube to support and to maintain the alignment of the optical resonator structure. The gas lasing medium is used within the support tube to maintain the tube at a substantially constant temperature above the ambient. Furthermore, an active temperature controller is disclosed. The temperature controller maintains the gas lasing medium in the support tube at a substantially constant temperature. An active pressure controller is also disclosed. The active pressure controller uses a pressure sensor, an electronic processor, and a motor-driven needle valve to maintain the pressure of the gas lasing medium in the laser within the desired operating pressure range. The laser can also be switched in operation from a continuous mode to a pulsing mode. An active power control system is disclosed wherein the power output of the laser, through an active feedback loop is maintained at the desired level.