the ground to first excited state of the li 2 ion re radiation to the ground state occurs within 26 psec with the emission of a 13 5 nm photon the lithium ion is then available for a further cycle of excitation and radiation the 13 5 nm extreme ultraviolet light is most intense from the absorption volume defined by the focal spot diameter of the heating laser and the absorption depth this volume may therefore be tuned in shape and size to optimize illumination uniformity in lithography or another use provided the absorbed laser power dominates heat transport out of the absorption region by plasma thermal conduction there will be efficient conversion of absorbed light at 10 6 u03bcm into euv radiation at 13 5 in occurring within a volume of approximately the same size as the absorption volume the linear geometry of a z pinch with its strong azimuthal self field acts as a natural heat trap because the conduction of heat is only significant along the axis of the pinch it may be shown that an axial heat flow of one to several kw can exist close to the laser absorption region so the laser power should be greater than a few kw for optimum small plasma size to avoid u201c smearing u201d by thermal diffusion an embodiment of the invention is shown in its entirety in fig1 and the central discharge region in fig1.