Improved performance of recombination Balmer‐α laser by short pulse irradiation

Short pulse pumping is required to isoelectronically scale recombination Balmer‐α laser to shorter wavelengths. By irradiating a planar NaF target with a 28 ps laser pulse, gain coefficient of 4 cm−1 has been attained on time‐ and space‐integrated measurement. This gain is approximately a factor of 3 larger than the value we have obtained previously in target irradiation with a 130 ps laser pulse. Peak gain local in space and time of 18 cm−1 is suggested in computer simulation. A 3.5 ps, 8 TW pulse been generated by chirped pulse amplification which may be applicable to extension of the Blamer‐α laser to shorter wavelengths.