Generation of attosecond (10^-18s) and zeptosecond (10^-21s) x-ray pulses. The carrier-envelope phase of the high power femtosecond driving laser in our lab is stabilized using the “grating shaker” technique we invented. The Double Optical Gating method is refined to generate shorter and stronger single isolated attosecond pulses with both few-cycle and multicycle lasers. We are working on the PROOF method for characterizing ultrabroad bandwidth attosecond and zeptosecond pulses. In the mean time, we are applying the unique attosecond light source to study correlated electron motions in atoms, molecules and condensed matters.