Using the stimulated Brillouin scattering phase conjugation and pulse compression technique, a conventional long pulse ruby laser was successfully converted to give 300 ps pulses at 1 J energy level. The technique allows the use of smaller amplifiers than required in a conventional short pulse laser which in turn leads to operation at increased repetition rate. The completed laser when operated at 1.5 Hz produces stable output parameters. Each laser pulse is characterized by a sharp rise and a measured pre‐pulse level of less than 10−6of the main pulse, making it suitable for LIDAR Thomson scattering measurements.