MRI: Development of an Isolated Attosecond Pulse Spectrometer at the Carbon K Edge

University Of California-Berkeley, Berkeley CA

Investigators

Abstract

With this award from the award from the Major Research Instrumentation (MRI) and the Chemistry Research Instrumentation (CRIF) Programs, Professor Stephen Leone from the University of California Berkeley and colleagues Daniel Neumark, Roger Falcone and Feng Wang have developed an attosecond spectrometer system to measure fast processes when electrons are excited in materials containing carbon. This is a benchtop laboratory system with a laser source generating pulses in an energy range called the carbon K-edge. When electrons are excited by this laser pulse, the dynamic process that result (molecular fragmentation, or rearrangement of other electrons) are observed. These processes can be very fast, on an attosecond time scale (10 to the minus 18 seconds). The processes are probed with such time-scale pulses of light as they occur. Initial experiments have demonstrated the operational proof-of-principle. Applications will proceed on various carbon-containing materials. In the long term, progress will allow new measurements and basic knowledge to be generated on electronic properties of materials, electronics and biological systems. In the process of building this system students interact with expert builders helping in the formation of the new generation of instrument builders. The award addresses the development of a laser system and apparatus that can produce high order harmonics and isolated attosecond pulses up to and through the carbon K edge (300 eV). A robust system is built that can perform dynamical attosecond experiments at the carbon K edge on a daily basis. The proposal is aimed at enhancing research and education at all levels, especially to (a) develop robust attosecond pulses, (b) study charge migration in molecules, (c) explore photodissociation dynamics and isomerization in prototype systems, (d) study electronic coherences and (e) analyze solid state and many-body charge state dynamics.