Efficient generation of vacuum and extreme ultraviolet pulses

We demonstrated efficient vacuum and extreme ultraviolet third harmonic generation driven by intense ultrashort fundamental-wave pulses. As the driving pulses were tightly focused upon an argon gas jet to reach relatively high peak intensities, we achieved vacuum ultraviolet pulse energy of 6.4 μJ at 133 nm and extreme ultraviolet (XUV) pulse energy of 199 nJ at 89 nm, with the corresponding conversion efficiency up to 0.26‰ and 0.008‰, respectively. In addition, the intense 400-nm ultrashort driving pulse was up-converted to a 79-nm XUV pulse with pulse energy of 251 nJ and the harmonic generation efficiency was 0.01‰.