Pump-Probe Study of Bi1-xSbx Alloys

1992 ◽  
Vol 291 ◽  
Author(s):  
J. Vidal ◽  
T.K. Cheng ◽  
A.W. Fung ◽  
H.J. Zeiger ◽  
G. Dresselhaus ◽  
...  
Keyword(s):  
Relaxation Time ◽  
Lattice Dynamics ◽  
Optical Response ◽  
Vibrational Frequencies ◽  
Oscillatory Behavior ◽  
Lattice Vibrations ◽  
Time Resolved ◽  
Pump Probe ◽  
Model Based ◽  
Reflectivity Signal

ABSTRACTBi1-xSbx alloys undergo a semimetal-semiconductor transition at x = 0.065 and 0.22 and are semiconducting between these limits. We investigate this system by means of femtosecond time-resolved experiments, and observe an optical response similar to those in Bi, Sb, Te and Ti2O3. A previously-reported model describes the mechanism of generation of coherent lattice vibrations via the optically excited carriers in this class of materials. As predicted by the model, the modulated reflectivity signal ΔR/R in Bi.88Sb.12 shows a beating oscillatory behavior with the Bi-Bi and Bi-Sb A1g vibrational frequencies. Model-based calculations of the ΔR background relaxation time at different Sb compositions provide understanding of the carrier and lattice dynamics throughout the transition.

scholarly journals Four-dimensional imaging of lattice dynamics using ab-initio simulation

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Navdeep Rana ◽  
Aditya Prasad Roy ◽  
Dipanshu Bansal ◽  
Gopal Dixit
Keyword(s):  
Inelastic Scattering ◽  
Momentum Space ◽  
Lattice Dynamics ◽  
Inelastic Neutron Scattering ◽  
Scattering Data ◽  
Time Resolved ◽  
Pump Probe ◽  
Theoretical Simulation ◽  
X Ray ◽  
Displacive Phase Transition

AbstractTime-resolved mapping of lattice dynamics in real- and momentum-space is essential to better understand several ubiquitous phenomena such as heat transport, displacive phase transition, thermal conductivity, and many more. In this regard, time-resolved diffraction and microscopy methods are employed to image the induced lattice dynamics within a pump–probe configuration. In this work, we demonstrate that inelastic scattering methods, with the aid of theoretical simulation, are competent to provide similar information as one could obtain from the time-resolved diffraction and imaging measurements. To illustrate the robustness of the proposed method, our simulated result of lattice dynamics in germanium is in excellent agreement with the time-resolved x-ray diffuse scattering measurement performed using x-ray free-electron laser. For a given inelastic scattering data in energy and momentum space, the proposed method is useful to image in-situ lattice dynamics under different environmental conditions of temperature, pressure, and magnetic field. Moreover, the technique will profoundly impact where time-resolved diffraction within the pump–probe setup is not feasible, for instance, in inelastic neutron scattering.

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.

Investigation on nonlinear dynamics of ZnO using time-resolved pump-probe technique with phase object

2011 ◽  
Author(s):  
Lirong Ge ◽  
Min Shui ◽  
Xiao Jin ◽  
Zhongguo Li ◽  
Yinglin Song
Keyword(s):  
Nonlinear Dynamics ◽  
Phase Object ◽  
Time Resolved ◽  
Pump Probe ◽  
Probe Technique

scholarly journals Selective time-dependent changes of Cu(DPPE)(DMP)·PF6on photoexcitation

2014 ◽  
Vol 70 (a1) ◽  
pp. C776-C776 ◽  
Author(s):  
Elzbieta Trzop ◽  
Bertrand Fournier ◽  
Katarzyna Jarzembska ◽  
Jesse Sokolow ◽  
Radoslaw Kaminski ◽  
...  
Keyword(s):  
Structural Changes ◽  
Dye Sensitized Solar Cells ◽  
Department Of Energy ◽  
Data Sets ◽  
Monoclinic System ◽  
Time Resolved ◽  
Pump Probe ◽  
Light Emitting Devices ◽  
Potential Applications ◽  
Photon Source

Thanks to their potential applications as light-emitting devices, chemical sensors and dye-sensitized solar cells, heteroleptic copper (I) complexes have been extensively studied. Cu(DPPE)(DMP)·PF6(dppe= 1,2-bis(diphenylphosphino)ethane; dmp = 2,9-dimethyl-1,10-phenanthroline) crystallizes in the monoclinic system, P21/c, with two independent molecules in the asymmetric unit. Previous studies on this system [1,2] show strong temperature-dependent emission. The complex was studied at 90K under 355nm laser excitation. At this temperature, the luminescence decay for Cu(DPPE)(DMP)·PF6is biexponential with lifetimes of ~3μs and ~28μs. Two time-resolved X-ray diffraction techniques were applied for studies: (1) a Laue technique at BioCARS ID-14 beamline at the Advanced Photon Source, and (2) monochromatic diffraction at a newly constructed in-house pump-probe monochromatic facility at the University at Buffalo. Structural changes determined with the two methods are in qualitative agreement; discrepancies in position of the Cu and P atoms were observed. The molecular distortions were smaller than those determined at 16K in the earlier synchrotron study by Vorontsov et al. [2]. Photodeformation maps (see Figure below), in which the increase in temperature on photoexcitation has been eliminated, clearly illustrate the photoinduced atomic shifts for both data sets. Results will be compared with those obtained for other studied heteroleptic copper (I) complexes, for instance Cu[(1,10-phenanthroline-N,N′) bis(triphenylphosphine)]·BF4[3]. The in-house pump-probe facility is discussed by Radoslaw Kaminski at this meeting. Research funded by the National Science Foundation (CHE1213223). BioCARS Sector 14 at APS is supported by NIH (RR007707). The Advanced Photon Source is funded by the Office of Basic Energy Sciences, U.S. Department of Energy, (W-31-109-ENG-38). KNJ is supported by the Polish Ministry of Science and Higher Education through the "Mobility Plus" program.

Ultrafast relaxation investigated by Photoelectron Circular Dichroism : an isomeric comparison of Camphor and Fenchone

2021 ◽  
Author(s):  
Valérie Blanchet ◽  
Dominique Descamps ◽  
stephane Petit ◽  
Yann Mairesse ◽  
bernard Pons ◽  
...  
Keyword(s):  
Circular Dichroism ◽  
Imaging Technique ◽  
Velocity Map Imaging ◽  
Relaxation Dynamics ◽  
Time Resolved ◽  
Pump Probe ◽  
Ultrafast Relaxation ◽  
Circular Dichroïsm ◽  
Isomeric Effects

We study isomeric effects using time resolved photoelectron circular dichroism (PECD). By a (1+1’)pump-probe ionisation with photoelectron collected by velocity map imaging technique, we compare relaxation dynamics from the 3s-Rydberg...

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