Temporal cross-correlation of x-ray free electron and optical lasers using soft x-ray pulse induced transient reflectivity.

The recent development of x-ray free electron lasers providing coherent, femtosecond-long pulses of high brilliance and variable energy opens new areas of scientific research in a variety of disciplines such as physics, chemistry, and biology. Pump-probe experimental techniques which observe the temporal evolution of systems after optical or x-ray pulse excitation are one of the main experimental schemes currently in use for ultrafast studies. The key challenge in these experiments is to reliably achieve temporal and spatial overlap of the x-ray and optical pulses. Here we present measurements of the x-ray pulse induced transient change of optical reflectivity from a variety of materials covering the soft x-ray photon energy range from 500eV to 2000eV and outline the use of this technique to establish and characterize temporal synchronization of the optical-laser and FEL x-ray pulses.

[1]  J. Hajdu,et al.  Ultrafast Bond Softening in Bismuth: Mapping a Solid's Interatomic Potential with X-rays , 2007, Science.

[2]  K. Matsubayashi,et al.  Pressure-induced magnetic phase transition in gold-phase SmS , 2004 .

[3]  J. Hajdu,et al.  Time-resolved pump-probe experiments at the LCLS. , 2010, Optics express.

[4]  Regina Soufli,et al.  Linac Coherent Light Source soft x-ray materials science instrument optical design and monochromator commissioning. , 2011, The Review of scientific instruments.

[5]  Carson,et al.  Valence-band electronic structure of silicon nitride studied with the use of soft-x-ray emission. , 1986, Physical review. B, Condensed matter.

[6]  Martin Beye,et al.  X-ray pulse preserving single-shot optical cross-correlation method for improved experimental temporal resolution , 2012 .

[7]  G. Zhao,et al.  ELECTRONIC STRUCTURE AND CHARGE TRANSFER IN ALPHA - AND BETA -SI3N4 AND ATTHE SI(111)/SI3N4(001) INTERFACE , 1998 .

[8]  P. Balcou,et al.  Observation of a Train of Attosecond Pulses from High Harmonic Generation , 2001, Science.

[9]  D. Ratner,et al.  First lasing and operation of an ångstrom-wavelength free-electron laser , 2010 .

[10]  J. P. Callan,et al.  GaAs under Intense Ultrafast Excitation: Response of the Dielectric Function , 1998 .

[11]  C. Bostedt,et al.  Spectral encoding of x-ray/optical relative delay. , 2011, Optics express.

[12]  H. Kumigashira,et al.  Precise determination of band offsets and chemical states in SiN∕Si studied by photoemission spectroscopy and x-ray absorption spectroscopy , 2005 .

[13]  Stephen C. Rand,et al.  Optical properties of silicon nitride films deposited by hot filament chemical vapor deposition , 1995 .

[14]  J. Feldhaus,et al.  Time-to-space mapping in a gas medium for the temporal characterization of vacuum-ultraviolet pulses , 2007 .

[15]  T. N. Hansen,et al.  Clocking femtosecond X rays. , 2005, Physical review letters.

[16]  L. Juha,et al.  The soft x-ray instrument for materials studies at the linac coherent light source x-ray free-electron laser. , 2012, The Review of scientific instruments.

[17]  Z. Fisk,et al.  Electron tunneling into intermediate-valence materials. [CePd/sub 3/] , 1982 .

[18]  M. Drescher,et al.  Time-resolved ion spectrometry on xenon with the jitter-compensated soft x-ray pulses of a free-electron laser , 2009 .

[19]  Eugene T. Kennedy,et al.  Single-shot characterization of independent femtosecond extreme ultraviolet free electron and infrared laser pulses , 2007 .

[20]  Wilfried Wurth,et al.  Single-shot timing measurement of extreme-ultraviolet free-electron laser pulses , 2008 .

[21]  J. P. Callan,et al.  Ultrafast electron and lattice dynamics in semiconductors at high excited carrier densities , 2000 .

[22]  M. Murnane,et al.  Laser-assisted photoemission from surfaces , 2007, 2007 Quantum Electronics and Laser Science Conference.

[23]  Martin Beye,et al.  A femtosecond X-ray/optical cross-correlator , 2008 .

[24]  Hani E. Elsayed-Ali,et al.  Observation of surface enhanced multiphoton photoemission from metal surfaces in the short pulse limit , 1995 .