# US 5,347,530 A · Pulsed gas-discharge laser system > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 5,347,530 A - Document ID: US5347530A - Status: Granted - Kind: A - Application number: 07/958,336 - Filed: 1993-02-11 - Granted: 1994-09-13 - Earliest claimed: 1991-04-20 - Assignees: Deutsche Forschungsanstalt fuer Luft- und Raumfahrt e.V. - Inventors: Frank Gekat; Hans Klingenberg; Gerhard Krutina - Web page: https://patentgrep.com/patent/US5347530A ## CPC - H01S 3/0943: of a gas laser - H01S 3/0975: using inductive or capacitive excitation - H01S: DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL ## Abstract To provide a pulsed gas-discharge laser system, in particular a pulsed excimer laser system, comprising a resonator and a gas volume filled with laser gas in which a gas discharge is ignitable, a microwave discharge structure surrounding the gas volume at least partially for maintaining the gas discharge, a microwave source for generating a microwave pulse and a microwave line leading from the microwave source to the microwave discharge structure, in which the laser pulse power behaves overproportionally to the pumping power, it is proposed that there be coupled to the microwave line by a coupling element a resonant microwave storage structure which leads to the gas volume and extends with at least a partial section thereof between the microwave discharge structure and the microwave line, and that the microwave storage structure be of such design and coupled to the microwave line by the coupling element in such a way that it stores the energy from the microwave pulse emitted by the microwave source until the ignition of the gas discharge and after the ignition of the gas discharge maintains the latter with the stored energy. ## Claims ### Claim 1 A pulsed excimer laser system, comprising: a resonator; a gas volume filled with laser gas in which a gas discharge is ignitable; a microwave discharge structure at least partially surrounding the gas volume for maintaining the gas discharge; a microwave source for generating a microwave pulse; a microwave line leading from the microwave source to the microwave discharge structure via a coupling element; and a resonant microwave storage structure which communicates with the gas volume and includes at least a partial section extending between the microwave discharge structure and the microwave line; wherein the microwave storage structure stores the energy from the microwave pulse emitted by the microwave source until the ignition of the gas discharge and then maintains the gas discharge using the stored energy. ### Claim 2 (depends on 1) The system of claim 1, wherein the resonant microwave storage structure is coupled to the microwave line by the coupling element; and after the ignition of the gas discharge the resonant microwave storage structure couples back into the microwave line a microwave power which is at most double the microwave power of the microwave pulse. ### Claim 3 (depends on 1) The system of claim 1 wherein the microwaves in the microwave discharge structure have an electric field vector (E) which is perpendicular to an optical axis of the resonator. ### Claim 4 (depends on 3) The system of claim 3 wherein the electric field vector (E) penetrates a region of the gas volume in the microwave discharge structure which extends in the direction of an optical axis of the resonator at least 1.5 times the cut-off wavelength of the microwave discharge structure. ### Claim 5 (depends on 1) The system of claim 1 wherein the resonant microwave storage structure has a length which is approximately half of the path travelled by the microwaves during the gas discharge. ### Claim 6 (depends on 1) The system of claim 1 wherein the resonant microwave storage structure is formed substantially of electrically conductive materials. ### Claim 7 (depends on 1) The system of claim 1 wherein: the resonant microwave storage structure comprises a storage line and is integrally formed with the microwave discharge structure. ### Claim 8 (depends on 1) The system of claim 1 wherein the resonant microwave storage structure comprises an elongate resonant structure. ### Claim 9 (depends on 1) The system of claim 1 wherein the resonant microwave storage structure comprises a closed ring-resonant structure. ### Claim 10 (depends on 1) The system of claim 1 wherein the gas discharge is ignited in the gas volume by self-ignition. ### Claim 11 (depends on 1) The system of claim 1 wherein the gas discharge is ignited by preionization. ### Claim 12 (depends on 11) The system of claim 11 wherein the preionization is effected by an electric field (EV). ### Claim 13 (depends on 12) The system of claim 12 wherein the electric field is a high-frequency field. ### Claim 14 (depends on 11) The system of claim 11 wherein the preionization is effected by electromagnetic radiation. ### Claim 15 (depends on 14) The system of claim 14 wherein the preionization is effected optically. ### Claim 16 (depends on 1) The system of claim 1 wherein: the resonant microwave storage structure comprises a storage waveguide which is coupled to the microwave line; and said resonant microwave storage structure is coupled to the microwave discharge structure via a switch element. ### Claim 17 (depends on 16) The system of claim 16 wherein when the switch element is switched on, the storage waveguide and the microwave coupling structure are tuned to one another such that the storage waveguide couples back into the microwave line a microwave power which is at most double the microwave power of the microwave pulse. ### Claim 18 (depends on 16) The system of claim 16 wherein the switch element comprises an H-T element. ### Claim 19 (depends on 16) The system of claim 16 wherein the microwave discharge structure has a shape which promotes an essentially constant electric field (E) in the gas volume.