An electrical signal, such as a high current pulse, is applied to a series of two or more conducting strips (101-110) installed in series in a laser cavity (150, 151) containing either a buffer gas or a vacuum. The strips are separated by small gaps. When the electrical signal is applied to the strips, plasmas (141-149) are formed in the gap regions. The plasmas are comprised of ions from the strip material. Once formed, these plasmas expand hemispherically, cool and recombine to generate radiation. The composition of the plasmas depends on the strip material, the electric field in the gaps, the gap size and the background gas type and pressure.