Ultrafast pump-probe measurements of dense plasma conditions using an ultra-bright X-ray laser

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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Direct Detection of Pure ac Spin Current by X-Ray Pump-Probe Measurements

Physical Review Letters ◽

10.1103/physrevlett.117.076602 ◽

2016 ◽

Vol 117 (7) ◽

Cited By ~ 33

Author(s):

J. Li ◽

L. R. Shelford ◽

P. Shafer ◽

A. Tan ◽

J. X. Deng ◽

...

Keyword(s):

Direct Detection ◽

Spin Current ◽

Pump Probe ◽

X Ray ◽

Probe Measurements

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Resonant soft x-ray scattering endstation for time-resolved pump-probe measurements at LCLS

10.1117/12.931492 ◽

2012 ◽

Author(s):

Yi-De Chuang ◽

Dionisio Doering ◽

Alejandro G. Cruz ◽

Nadeem Tahir ◽

Nord C. Andresen ◽

...

Keyword(s):

Time Resolved ◽

Pump Probe ◽

X Ray ◽

X Ray Scattering ◽

Probe Measurements ◽

Ray Scattering

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Pump-Probe Measurements Using Silicon Nanocrystal Waveguides

MRS Proceedings ◽

10.1557/proc-770-i3.2 ◽

2003 ◽

Vol 770 ◽

Cited By ~ 1

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.

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Giant Photoluminescence Enhancement and Carrier Dynamics in MoS2 Bilayers with Anomalous Interlayer Coupling

Nanomaterials ◽

10.3390/nano11081994 ◽

2021 ◽

Vol 11 (8) ◽

pp. 1994

Author(s):

Han Li ◽

Yating Ma ◽

Zhongjie Xu ◽

Xiang’ai Cheng ◽

Tian Jiang

Keyword(s):

Optical Properties ◽

Transition Metal Dichalcogenides ◽

Interlayer Coupling ◽

Carrier Dynamics ◽

Probe Signal ◽

Exciton Resonance ◽

Pump Probe ◽

Metal Dichalcogenides ◽

Photoluminescence Enhancement ◽

Probe Measurements

Fundamental researches and explorations based on transition metal dichalcogenides (TMDCs) mainly focus on their monolayer counterparts, where optical densities are limited owing to the atomic monolayer thickness. Photoluminescence (PL) yield in bilayer TMDCs is much suppressed owing to indirect-bandgap properties. Here, optical properties are explored in artificially twisted bilayers of molybdenum disulfide (MoS2). Anomalous interlayer coupling and resultant giant PL enhancement are firstly observed in MoS2 bilayers, related to the suspension of the top layer material and independent of twisted angle. Moreover, carrier dynamics in MoS2 bilayers with anomalous interlayer coupling are revealed with pump-probe measurements, and the secondary rising behavior in pump-probe signal of B-exciton resonance, originating from valley depolarization of A-exciton, is firstly reported and discussed in this work. These results lay the groundwork for future advancement and applications beyond TMDCs monolayers.

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