Phase-Sensitive Control Of Molecular Dissociation Through Attosecond Pump/Strong-Field Mid-IR Probe Spectroscopy
Technical Report,01 Apr 2012,30 Nov 2015
Massachusetts Institute of Technology Cambridge United States
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Our program developed key technologies for strong-field and attosecond physics, specifically towards the goal of sequentially controlling ionization and dissociation steps in the H2 molecule using tightly synchronized few-fs EUV and few-cycle mid-IR pulses. We developed a cryocooled laser and optical parametric chirped pulse amplification based light pulse architecture, producing, by high harmonic generation, a 16-18 eV isolated single-femtosecond EUV pulse source, and by adiabatic difference frequency generation and optical parametric amplification, octavespanning energetic mid-IR pulses at 2.6 and 6 micron wavelengths. In addition, we developed improvements to the FROG-CRAB attosecond EUV pulse characterization method to aid precision attosecond spectroscopy experimentation, and a two-color EUVmid-IR pump probe ionspectroscopy system, employing coherent wavelength multiplexing for tight synchronization between optical pulses, an actively stabilized Mach-Zender interferometer for scanning the delay between these pulses under vacuum, and a vacuum target chamber allowing the sequential use of electron and ion time-of-flight spectrometers for in situ EUV pulse characterization and ion spectroscopy of strong-field molecular dissociation dynamics. The scalability of this system in average power and repetition frequency will allow for a powerful strong-field physics platform.