An all-solid-state laser system produces coherent DUV radiation through a third or fourth harmonic generation. The fundamental wavelength is generated by a slave laser optically pumped by one or more light source(s) of high density array(s) and is stabilized by injecting optical seeds whose wavelength is rapidly swept to cover the fundamental wavelength. The pump effects are enhanced by a pump chamber that recycles unabsorbed pump light. The present invention enables DUV pulses with a width shorter than 1 ns and a repetition rate higher than 100 kHz. The output DUV wavelength is adjustable by selecting an appropriate seeder.