...VASILEIOS-MARIOS GKORTSAS vasilisg@mit.edu 6.638 Term Paper Attosecond Pulse Generation Abstract: The word “attosecond” (1 as = 10-18 sec) entered the vocabulary of physics when sub-femtosecond pulses of UV/XUV light were established. High harmonic generation (HHG) is currently the only experimentally proven method for generating attosecond pulses. Attosecond science has opened the door to real-time observation and time-domain control of atomic-scale electron dynamics. In this work, we review the essentials of the generation of attosecond pulses and we mention the applications of attosecond science in the control of electronic motion. 1. Introduction The need for finer time resolution and the quest for higher peak power explain the continuous trend towards shorter laser pulses since the invention of the laser. The historical progress of ultra-short technology is summarized in Figure 1. The first pulse lasers had duration of several hundreds of microseconds. The invention of Q-switching (Hellwarth, 1961) reduced the pulse length to 10 ns (four orders of magnitude decrease). The invention of laser mode locking (DiDomenico, 1964; Hargrove et al., 1964; Siegman, 1970) accompanied by broad gain laser media (Shank and Ippen 1974) further reduced the duration to less than 1 ps (another four orders of magnitude decrease). The ring cavity with intra-cavity prism compensation of the group velocity dispersion produced pulses of 6 fs (Fork et al, 1987)...
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