We have achieved spectrum narrowing to 1 pm in a high‐power ArF excimer laser injection locked by an all solid‐state fourth harmonic (193.4 nm) seed source of 773.6 nm Ti:sapphire laser radiation. Superior laser properties such as sufficient output energy (90 mJ/pulse, 50 pps), locking efficiency exceeding 90%, wavelength drift less than 0.4 pm, and spectrum bandwidth fluctuation less than 0.2 pm were obtained, which meet the requirements for 1 Gbit dynamic random access memory microlithography. ©1995 American Institute of Physics.