scholarly journals Time-resolved x-ray/optical pump-probe simulations on N2 molecules

2019 ◽  
Vol 6 (2) ◽  
pp. 024101
Author(s):  
Athiya Mahmud Hanna ◽  
Oriol Vendrell ◽  
Robin Santra
Keyword(s):  
Optical Pump ◽  
Time Resolved ◽  
Pump Probe ◽  
X Ray

scholarly journals Pump-Probe Time-Resolved Serial Femtosecond Crystallography at SACLA: Current Status and Data Collection Strategies

2019 ◽  
Vol 9 (24) ◽  
pp. 5505 ◽  
Author(s):  
Eriko Nango ◽  
Minoru Kubo ◽  
Kensuke Tono ◽  
So Iwata
Keyword(s):  
Data Collection ◽  
Free Electron ◽  
Free Electron Laser ◽  
Current Status ◽  
Optical Pump ◽  
Time Resolved ◽  
Pump Probe ◽  
X Ray ◽  
Collection Strategies ◽  
Serial Femtosecond Crystallography

Structural information on protein dynamics is a critical factor in fully understanding the protein functions. Pump-probe time-resolved serial femtosecond crystallography (TR-SFX) is a recently established technique for visualizing the structural changes or reactions in proteins that are at work with high spatial and temporal resolution. In the pump-probe method, protein microcrystals are continuously delivered from an injector and exposed to an X-ray free-electron laser (XFEL) pulse after a trigger to initiate a reaction, such as light, chemicals, temperature, and electric field, which affords the structural snapshots of intermediates that occur in the protein. We are in the process of developing the device and techniques for pump-probe TR-SFX while using XFEL produced at SPring-8 Angstrom Compact Free-Electron Laser (SACLA). In this paper, we described our current development details and data collection strategies for the optical pump X-ray probe TR-SFX experiment at SACLA and then reported the techniques of in crystallo TR spectroscopy, which is useful in clarifying the nature of reaction that takes place in crystals in advance.

Pump-Probe Measurements Using Silicon Nanocrystal Waveguides

2003 ◽  
Vol 770 ◽  
Author(s):  
Nathanael Smith ◽  
Max J. Lederer ◽  
Marek Samoc ◽  
Barry Luther-Davies ◽  
Robert G. Elliman
Keyword(s):  
Probe Beam ◽  
Time Resolution ◽  
Pump Beam ◽  
Silicon Nanocrystals ◽  
Continuous Wave ◽  
Optical Gain ◽  
Optical Pump ◽  
Time Resolved ◽  
Pump Probe ◽  
Probe Measurements

AbstractOptical pump-probe measurements were performed on planar slab waveguides containing silicon nanocrystals in an attempt to measure optical gain from photo-excited silicon nanocrystals. Two experiments were performed, one with a continuous-wave probe beam and a pulsed pump beam, giving a time resolution of approximately 25 ns, and the other with a pulsed pump and probe beam, giving a time resolution of approximately 10 ps. In both cases the intensity of the probe beam was found to be attenuated by the pump beam, with the attenuation increasing monotonically with increasing pump power. Time-resolved measurements using the first experimental arrangement showed that the probe signal recovered its initial intensity on a time scale of 45-70 μs, a value comparable to the exciton lifetime in Si nanocrystals. These data are shown to be consistent with an induced absorption process such as confined carrier absorption. No evidence for optical gain was observed.

scholarly journals The time-resolved hard X-ray diffraction endstation KMC-3 XPP at BESSY II

2021 ◽  
Vol 28 (3) ◽  
Author(s):  
Matthias Rössle ◽  
Wolfram Leitenberger ◽  
Matthias Reinhardt ◽  
Azize Koç ◽  
Jan Pudell ◽  
...  
Keyword(s):  
Storage Ring ◽  
Single Photon ◽  
Laser System ◽  
High Vacuum ◽  
Laser Pulses ◽  
Pixel Detector ◽  
X Ray Diffraction ◽  
Optical Pump ◽  
Time Resolved ◽  
X Ray

The time-resolved hard X-ray diffraction endstation KMC-3 XPP for optical pump/X-ray probe experiments at the electron storage ring BESSY II is dedicated to investigating the structural response of thin film samples and heterostructures after their excitation with ultrashort laser pulses and/or electric field pulses. It enables experiments with access to symmetric and asymmetric Bragg reflections via a four-circle diffractometer and it is possible to keep the sample in high vacuum and vary the sample temperature between ∼15 K and 350 K. The femtosecond laser system permanently installed at the beamline allows for optical excitation of the sample at 1028 nm. A non-linear optical setup enables the sample excitation also at 514 nm and 343 nm. A time-resolution of 17 ps is achieved with the `low-α' operation mode of the storage ring and an electronic variation of the delay between optical pump and hard X-ray probe pulse conveniently accesses picosecond to microsecond timescales. Direct time-resolved detection of the diffracted hard X-ray synchrotron pulses use a gated area pixel detector or a fast point detector in single photon counting mode. The range of experiments that are reliably conducted at the endstation and that detect structural dynamics of samples excited by laser pulses or electric fields are presented.

scholarly journals Decomposing electronic and lattice contributions in optical pump – X-ray probe transient inner-shell absorption spectroscopy of CuO

2019 ◽  
Vol 216 ◽  
pp. 414-433 ◽  
Author(s):  
Johannes Mahl ◽  
Stefan Neppl ◽  
Friedrich Roth ◽  
Mario Borgwardt ◽  
Catherine Saladrigas ◽  
...  
Keyword(s):  
Heat Transport ◽  
Absorption Spectroscopy ◽  
Energy Deposition ◽  
Optical Pump ◽  
Time Resolved ◽  
X Ray ◽  
X Ray Absorption

Laser-induced energy deposition and heat transport in CuO is studied by picosecond time-resolved X-ray absorption spectroscopy.

scholarly journals Probing Attosecond Electron Coherence in Molecular Charge Migration by Ultrafast X-Ray Photoelectron Imaging

2019 ◽  
Vol 9 (9) ◽  
pp. 1941 ◽  
Author(s):  
Kai-Jun Yuan ◽  
André D Bandrauk
Keyword(s):  
Electron Dynamics ◽  
Charge Migration ◽  
Photoelectron Imaging ◽  
Time Resolved ◽  
Pump Probe ◽  
New Approach ◽  
X Ray ◽  
Chemistry Research ◽  
Molecular Charge ◽  
Electron Coherence

Electron coherence is a fundamental quantum phenomenon in today’s ultrafast physics and chemistry research. Based on attosecond pump–probe schemes, ultrafast X-ray photoelectron imaging of molecules was used to monitor the coherent electron dynamics which is created by an XUV pulse. We performed simulations on the molecular ion H 2 + by numerically solving time-dependent Schrödinger equations. It was found that the X-ray photoelectron angular and momentum distributions depend on the time delay between the XUV pump and soft X-ray probe pulses. Varying the polarization and helicity of the soft X-ray probe pulse gave rise to a modulation of the time-resolved photoelectron distributions. The present results provide a new approach for exploring ultrafast coherent electron dynamics and charge migration in reactions of molecules on the attosecond time scale.

scholarly journals Unambiguous determination of spin dephasing times in ZnO by time-resolved magneto-optical pump-probe experiments

2014 ◽  
Vol 251 (9) ◽  
pp. 1861-1871 ◽  
Author(s):  
Sebastian Kuhlen ◽  
Ralph Ledesch ◽  
Robin de Winter ◽  
Matthias Althammer ◽  
Sebastian T. B. Gönnenwein ◽  
...  
Keyword(s):  
Optical Pump ◽  
Time Resolved ◽  
Pump Probe ◽  
Spin Dephasing ◽  
Unambiguous Determination

scholarly journals FemtoSpeX: a versatile optical pump–soft X-ray probe facility with 100 fs X-ray pulses of variable polarization

2014 ◽  
Vol 21 (5) ◽  
pp. 1090-1104 ◽  
Author(s):  
Karsten Holldack ◽  
Johannes Bahrdt ◽  
Andreas Balzer ◽  
Uwe Bovensiepen ◽  
Maria Brzhezinskaya ◽  
...  
Keyword(s):  
Laser System ◽  
X Ray Diffraction ◽  
Optical Pump ◽  
Time Resolved ◽  
Transient Phenomena ◽  
X Ray ◽  
User Facility ◽  
Average Flux ◽  
The Stability ◽  
Electron Storage Rings

Here the major upgrades of the femtoslicing facility at BESSY II (Khanet al., 2006) are reviewed, giving a tutorial on how elliptical-polarized ultrashort soft X-ray pulses from electron storage rings are generated at high repetition rates. Employing a 6 kHz femtosecond-laser system consisting of two amplifiers that are seeded by one Ti:Sa oscillator, the total average flux of photons of 100 fs duration (FWHM) has been increased by a factor of 120 to up to 106 photons s−1(0.1% bandwidth)−1on the sample in the range from 250 to 1400 eV. Thanks to a new beamline design, a factor of 20 enhanced flux and improvements of the stability together with the top-up mode of the accelerator have been achieved. The previously unavoidable problem of increased picosecond-background at higher repetition rates, caused by `halo' photons, has also been solved by hopping between different `camshaft' bunches in a dedicated fill pattern (`3+1 camshaft fill') of the storage ring. In addition to an increased X-ray performance at variable (linear and elliptical) polarization, the sample excitation in pump–probe experiments has been considerably extended using an optical parametric amplifier that supports the range from the near-UV to the far-IR regime. Dedicated endstations covering ultrafast magnetism experiments based on time-resolved X-ray circular dichroism have been either upgraded or, in the case of time-resolved resonant soft X-ray diffraction and reflection, newly constructed and adapted to femtoslicing requirements. Experiments at low temperatures down to 6 K and magnetic fields up to 0.5 T are supported. The FemtoSpeX facility is now operated as a 24 h user facility enabling a new class of experiments in ultrafast magnetism and in the field of transient phenomena and phase transitions in solids.

scholarly journals XPP: X-ray Pump Probe station at BESSY II

2016 ◽  
Vol 2 ◽  
Author(s):  
Matthias Reinhardt ◽  
Wolfram Leitenberger
Keyword(s):  
Soft Matter ◽  
Ambient Conditions ◽  
X Ray Diffraction ◽  
Time Resolved ◽  
Pump Probe ◽  
X Ray ◽  
Experimental Station

The X-ray Pump-Probe (XPP) experimental station predominantly aims at investigating hard and soft matter under a broad range of ambient conditions using time-resolved X-ray diffraction.

scholarly journals Coherent ac spin current transmission across an antiferromagnetic CoO insulator

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Q. Li ◽  
M. Yang ◽  
C. Klewe ◽  
P. Shafer ◽  
A. T. N’Diaye ◽  
...  
Keyword(s):  
Spin Current ◽  
Spin Precession ◽  
Fundamental Physics ◽  
Time Resolved ◽  
Pump Probe ◽  
Insulating Layer ◽  
X Ray ◽  
Current Transmission ◽  
Measurement Results ◽  
Probe Measurements

AbstractThe recent discovery of spin current transmission through antiferromagnetic insulating materials opens up vast opportunities for fundamental physics and spintronics applications. The question currently surrounding this topic is: whether and how could THz antiferromagnetic magnons mediate a GHz spin current? This mismatch of frequencies becomes particularly critical for the case of coherent ac spin current, raising the fundamental question of whether a GHz ac spin current can ever keep its coherence inside an antiferromagnetic insulator and so drive the spin precession of another ferromagnet layer coherently? Utilizing element- and time-resolved x-ray pump-probe measurements on Py/Ag/CoO/Ag/Fe75Co25/MgO(001) heterostructures, here we demonstrate that a coherent GHz ac spin current pumped by the Py ferromagnetic resonance can transmit coherently across an antiferromagnetic CoO insulating layer to drive a coherent spin precession of the Fe75Co25 layer. Further measurement results favor thermal magnons rather than evanescent spin waves as the mediator of the coherent ac spin current in CoO.

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