scholarly journals Ultrafast strain engineering and coherent structural dynamics from resonantly driven optical phonons in LaAlO3

2020 ◽  
Vol 5 (1) ◽  
Author(s):  
J. R. Hortensius ◽  
D. Afanasiev ◽  
A. Sasani ◽  
E. Bousquet ◽  
A. D. Caviglia
Keyword(s):  
Lattice Dynamics ◽  
High Efficiency ◽  
Wave Packets ◽  
Strain Engineering ◽  
High Symmetry ◽  
Optical Pump ◽  
Time Resolved ◽  
Phase Switching ◽  
Material Control ◽  
Oxide Electronics

AbstractStrain engineering has been extended recently to the picosecond timescales, driving ultrafast metal–insulator phase transitions and the propagation of ultrasonic demagnetization fronts. However, the nonlinear lattice dynamics underpinning interfacial optoelectronic phase switching have not yet been addressed. Here we perform time-resolved all-optical pump-probe experiments to study ultrafast lattice dynamics initiated by impulsive light excitation tuned in resonance with a polar lattice vibration in LaAlO3 single crystals, one of the most widely utilized substrates for oxide electronics. We show that ionic Raman scattering drives coherent rotations of the oxygen octahedra around a high-symmetry crystal axis. By means of DFT calculations we identify the underlying nonlinear phonon–phonon coupling channel. Resonant lattice excitation is also shown to generate longitudinal and transverse acoustic wave packets, enabled by anisotropic optically induced strain. Importantly, shear strain wave packets are found to be generated with high efficiency at the phonon resonance, opening exciting perspectives for ultrafast material control.

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.

Dirac Surface Plasmons in Photoexcited Bismuth Telluride Nanowires : Optical Pump-Terahertz Probe Spectroscopy

Nanoscale ◽  
2021 ◽  
Author(s):  
Mithun K P ◽  
Srabani Kar ◽  
Abinash Kumar ◽  
Victor Suvisesha Muthu Dharmaraj ◽  
Ravishankar Narayanan ◽  
...  
Keyword(s):  
Surface Plasmons ◽  
Bismuth Telluride ◽  
Topological Insulators ◽  
Collective Excitation ◽  
Optical Pump ◽  
Time Resolved ◽  
Mid Infrared ◽  
Plasmonic Materials ◽  
Probe Spectroscopy

Collective excitation of Dirac plasmons in graphene and topological insulators have opened new possibilities of tunable plasmonic materials ranging from THz to mid-infrared regions. Using time resolved Optical Pump -...

Effects of insertion of strain-engineering Ga(In)NAs layers on optical properties of InAs/GaAs quantum dots for high-efficiency solar cells

2016 ◽  
Vol 52 ◽  
pp. 177-180 ◽  
Author(s):  
Emil-Mihai Pavelescu ◽  
Ville Polojärvi ◽  
Andreas Schramm ◽  
Antti Tukiainen ◽  
Arto Aho ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Optical Properties ◽  
Solar Cells ◽  
High Efficiency ◽  
Strain Engineering ◽  
High Efficiency Solar Cells

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.

Time-resolved Imaging of H2 + (D2 +) Nuclear Wave Packets

2007 ◽  
pp. 561-563
Author(s):  
Th. Ergler ◽  
A. Rudenko ◽  
B. Feuerstein ◽  
K. Zrost ◽  
C. D. Schröter ◽  
...  
Keyword(s):  
Wave Packets ◽  
Time Resolved ◽  
Time Resolved Imaging

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 Kinetics of a Phonon-Mediated Laser-Driven Structural Phase Transition in Sn2P2Se6

2019 ◽  
Vol 9 (3) ◽  
pp. 525
Author(s):  
Martin Kubli ◽  
Matteo Savoini ◽  
Elsa Abreu ◽  
Bulat Burganov ◽  
Gabriel Lantz ◽  
...  
Keyword(s):  
Structural Phase ◽  
Higher Order ◽  
High Temperature Phase ◽  
Incommensurate Phase ◽  
Temperature Phase ◽  
Complete Disappearance ◽  
X Ray Diffraction ◽  
Optical Pump ◽  
Time Resolved ◽  
The Time Domain

We investigate the structural dynamics of the incommensurately modulated phase of Sn 2P 2Se 6 by means of time-resolved X-ray diffraction following excitation by an optical pump. Tracking the incommensurable distortion in the time domain enables us to identify the transport effects leading to a complete disappearance of the incommensurate phase over the course of 100 ns. These observations suggest that a thin surface layer of the high-temperature phase forms quickly after photo-excitation and then propagates into the material with a constant velocity of 3.7 m/s. Complementary static structural measurements reveal previously unreported higher-order satellite reflection in the incommensurate phase. These higher-order reflections are attributed to cubic vibrational terms in the Hamiltonian.

Atomic electron wave packets studied with a time resolved phase-modulated technique

2005 ◽  
Author(s):  
B. Broers ◽  
J.F. Christian ◽  
J. Wals ◽  
H.H. Fielding ◽  
J.H. Hoogenraad ◽  
...  
Keyword(s):  
Wave Packets ◽  
Atomic Electron ◽  
Electron Wave ◽  
Time Resolved

Strain Engineering and Luminescence in Si/SiGe Three Dimensional Nanostructures

2011 ◽  
Vol 1305 ◽  
Author(s):  
Nikhil Modi ◽  
Leonid Tsybeskov ◽  
David J. Lockwood ◽  
Xiao Z. Wu ◽  
Jean Marc Baribeau
Keyword(s):  
Heavy Hole ◽  
Analytical Electron Microscopy ◽  
Three Dimensional ◽  
Strain Engineering ◽  
Partial Removal ◽  
Time Resolved ◽  
Germanium Content ◽  
Interface Recombination ◽  
Analytical Electron ◽  
Ge Nanocluster

ABSTRACTStrain engineering in composition-controlled Si-Si/Ge nanocluster multilayers with high germanium content (~ 50%) is achieved by varying thicknesses of Si/SiGe layers and studied by low temperature photoluminescence (PL) measurements. The PL spectra show reduction in strained silicon energy bandgap and a splitting presumably associated with partial removal of heavy hole-light hole degeneracy in SiGe valence band. Time-resolved PL measurements performed under different excitation wavelengths show dramatically different PL lifetimes, ranging from ~ 2 μs to 10 ns and an unusually high PL quantum efficiency. The results are explained by using the Si/SiGe interface recombination model, which is supported by ultra-high resolution transmission and analytical electron microscopy measurements.

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