Abstract
We describe our implementation of a high repetition rate (54 kHz-6.5 MHz), high power (>10 W), laser system at the 7ID beamline at the Advanced Photon Source for laser pump/x-ray probe studies of optically driven molecular processes. Laser pulses at 1.06 μm wavelength and variable duration (10 or 130 ps) are synchronized to the storage ring rf signal to a precision of ∼250 fs rms. Frequency doubling and tripling of the laser radiation using nonlinear optical techniques have been applied to generate 532 and 355 nm light. We demonstrate that by combining a microfocused x-ray probe with focused optical laser radiation the requisite fluence (with <10 μJ/pulse) for efficient optical excitation can be readily achieved with a compact and commercial laser system at megahertz repetition rates. We present results showing the time-evolution of near-edge x-ray spectra of a well-studied, laser-excited metalloporphyrin, Ni(II)-tetramesitylporphyrin. The use of high repetition rate, short pulse lasers as pump sources will dramatically enhance the duty cycle and efficiency in data acquisition and hence capabilities for laser-pump/x-ray probe studies of ultrafast structural dynamics at synchrotron sources.
Original language | English (US) |
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Article number | 073110 |
Journal | Review of Scientific Instruments |
Volume | 82 |
Issue number | 7 |
DOIs | |
State | Published - Jul 2011 |
Funding
We acknowledge support from the U.S. Department of Energy (DOE) Office of Science, Division of Chemical, Geological and Biological Sciences under Contract No. DE-AC02-06CH11357. Use of the Advanced Photon Source, an Office of Science User Facility operated for DOE Office of Science by Argonne National Laboratory, was supported by the U.S. DOE under Contract No. DE-AC02-06CH11357.
ASJC Scopus subject areas
- Instrumentation