A pulse discharge laser is provided having a pair of electrodes disposed within a laser chamber pressurized with a high- pressure gas. A preionizer generator intermittently produces preionization energy to preionize the high pressure gas in the laser chamber. A pulse forming network intermittently supplies a ramping voltage to the pair of electrodes. When the high pressure gas in the laser chamber is not properly preionized by the preionization energy a damaging arc may occur and lasing will not occur by discharge of the ramping voltage on the electrodes.
A laser chamber in accordance with an embodiment of the present invention redirects the shock waves away from the discharge area and into other areas of the laser chamber where the shock waves can be dissipated. In conventional systems, the walls of the laser chamber, the heat exchanger and/or other components within the laser chamber provide surfaces for shock waves to be deflected back into the discharge region, thereby disturbing the energy stability of subsequent pulses. Thus, a laser chamber that redirects the shock waves away from the discharge area to be dissipated elsewhere advantageously maintains stability of the gas within the discharge area during pulsing.
One embodiment of the laser chamber has an electrode structure that defines a laser discharge area, a blower that circulates gas within the laser chamber and a heat exchanger with a surface area that defines a passage for the gas circulating within the laser chamber. The circuitous path defined by the heat exchanger allows shock waves to be directed away from the discharge region and dissipated in other areas of the laser chamber. Further, the additional surface area of the heat exchanger efficiently cools the thermally excited gas. In some embodiments, the heat exchanger is curved to create an inner surface area defining a space, and an outer surface.
A protrusion from the side wall of the laser chamber extends into the space defined by the heat exchanger thereby lengthening the passage for the circulating gas.
In another embodiment, the working volume of the laser chamber is increased through the addition of ancillary chambers. The ancillary chambers are fluidically coupled to the laser chamber and are positioned such that shock waves generated by high energy discharges of the electrodes propagate directly into the openings of the ancillary chambers. The shock waves may then dissipate within the ancillary chambers rather than being reflected back to the laser discharge area. Flow guides, such as blowers or flow vanes, may be included within the ancillary chambers. The flow guides within the ancillary chambers generate a circulation of gas within the ancillary chambers that supports the circulating gas within the laser chamber at the openings of the ancillary chambers. The flow guides (or other baffles) within the ancillary chambers also act to trap the shock waves within the ancillary chamber, allowing the shock waves to dissipate through the action of multiple reflections within the ancillary chambers. Thus, the gas flow within the laser chamber remains stable and uniform.
Refrences:
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