Demonstration of a 100 Hz repetition rate soft x-ray laser and gain-saturated sub-10 nm table-top lasers

We report the first operation of a table-top soft x-ray laser at 100 Hz repetition rate. This gain saturated laser produces 0.15mWaverage power in the 18.9 nm line of nickel-like molybdenum in the form of 1.5 μJ pulses. This is the highest average power reported to date from a compact coherent soft x-ray laser source operating at wavelengths shorter than 20 nm. The soft x-ray laser is excited by a diode-pumped chirped pulse amplification Yb:YAG laser that produces 1 J pulses of 5 ps duration. We have also demonstrated the efficient generation of sub-9 nm wavelength laser pulses of microjoule energy at 1 Hz repetition rate with a table-top laser. Gain-saturated lasing was obtained at 8.85 nm in nickel-like lanthanum ions. Isoelectronic scaling along the lanthanide series resulted in lasing at wavelengths as short as 7.36 nm. Simulations show that the collisionally broadened atomic transitions in these dense plasmas can support the amplification of sub-picosecond soft x-ray laser pulses.