A laser focusing system (330) for use in an EUV radiation source is described, the laser focusing system comprising: •—a first curved mirror (330.1) configured to receive a laser beam from a beam delivery system (320) and generate a first reflected laser beam (316); •—a second curved mirror (330.2) configured to receive the first reflected laser beam (316) and generate a second reflected laser beam (317), wherein the laser focusing system (330) is configured to focus the second reflected laser beam (317) to a target location (340) in a vessel (350) of the EUV radiation source (360).