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 -...

Probing Photoexcited Carriers in a Few-Layer MoS2 Laminate by Time-Resolved Optical Pump–Terahertz Probe Spectroscopy

ACS Nano ◽  
2015 ◽  
Vol 9 (12) ◽  
pp. 12004-12010 ◽  
Author(s):  
Srabani Kar ◽  
Y. Su ◽  
R. R. Nair ◽  
A. K. Sood
Keyword(s):  
Optical Pump ◽  
Time Resolved ◽  
Probe Spectroscopy

Dirac fermion relaxation and energy loss rate near the Fermi surface in monolayer and multilayer graphene

Nanoscale ◽  
2014 ◽  
Vol 6 (15) ◽  
pp. 8575-8578 ◽  
Author(s):  
C. W. Luo ◽  
P. S. Tseng ◽  
H.-J. Chen ◽  
K. H. Wu ◽  
L. J. Li
Keyword(s):  
Fermi Surface ◽  
Energy Loss ◽  
Loss Rate ◽  
Dirac Fermion ◽  
Ultrafast Dynamics ◽  
Multilayer Graphene ◽  
Dirac Fermions ◽  
Optical Pump ◽  
Mid Infrared ◽  
Probe Spectroscopy

Ultrafast dynamics of Dirac fermions near the Fermi surface in monolayer and multilayer graphene are revealed using optical pump mid-infrared probe spectroscopy.

Photoinduced Conductivity Dynamics Studies of MgB2 Thin Films

2003 ◽  
Vol 17 (18n20) ◽  
pp. 3675-3681 ◽  
Author(s):  
Jure Demsar ◽  
Richard D. Averitt ◽  
Antoinette J. Taylor ◽  
Won-Nam Kang ◽  
Heon Jung Kim ◽  
...  
Keyword(s):  
Superconducting State ◽  
Recovery Time ◽  
High Energy ◽  
Strong Temperature Dependence ◽  
Optical Pump ◽  
Time Resolved ◽  
State Recovery ◽  
Order Of Magnitude ◽  
Recovery Dynamics ◽  
Probe Spectroscopy

We present the first direct studies of photoinduced Cooper-pair breaking and subsequent superconducting state recovery dynamics by means of femtosecond time-resolved optical-pump terahertz probe spectroscopy focusing on the superconducting state recovery dynamics in MgB 2. The superconducting state recovery proceeds on the timescale of several hundred picoseconds and shows a strong temperature dependence. In particular, upon increasing the temperature the recovery time first decreases, reaches a minimum, followed by a quasi-divergence upon further increasing the temperature towards Tc. Moreover, the recovery time shows virtually no intensity dependence, even though the photoexcitation fluence is changed by over an order of magnitude. This suggests that pair recovery is goverend by a phonon-bottleneck mechanism, where the lifetime of high energy phonons (ℏω > 2Δ) is governed by their anharmonicity.

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.

Limits of Charge Carrier Transport in Halide Perovskites Revealed by Optical-Pump Terahertz-Probe Spectroscopy

2019 ◽  
Author(s):  
Hannes Hempel ◽  
Andrei Petsiu ◽  
Martin Stolterfoht ◽  
Pascal Becker ◽  
Dieter Neher ◽  
...  
Keyword(s):  
Charge Carrier ◽  
Carrier Transport ◽  
Charge Carrier Transport ◽  
Optical Pump ◽  
Halide Perovskites ◽  
Probe Spectroscopy

scholarly journals Two - Color Mid-Infrared Spectroscopy of Isoelectronic Centers in Silicon

2003 ◽  
Vol 770 ◽  
Author(s):  
N.Q. Vinh ◽  
T. Gregorkiewicz
Keyword(s):  
Excited States ◽  
Free Electron ◽  
Free Electron Laser ◽  
Materials Science ◽  
Time Resolved ◽  
Mid Infrared ◽  
Semiconductor Physics ◽  
Open Questions ◽  
Time Resolved Photoluminescence ◽  
Tunable Source

AbstractOne of the open questions in semiconductor physics is the origin of the small splittings of the excited states of bound excitons in silicon. A free electron laser as a tunable source of the mid-infrared radiation (MIR) can be used to investigate such splittings of the excited states of optical centers created by transition metal dopants in silicon. In the current study, the photoluminescence from silver and copper doped silicon is investigated by two color spectroscopy in the visible and the MIR. It is shown the PL due recombination of exciton bound to Ag and Cu is quenched upon application of the MIR beam. The time-resolved photoluminescence measurements and the quenching effects of these bands are presented. By scanning the wavelength of the free-electron laser ionization spectra of relevant traps involved in photoluminescence are obtained. The formation and dissociation of the bound excitons, and the small splittings of the effective-mass excited states are discussed. The applied experimental method allows correlation of DLTS data on trapping centers to specific channels of radiative recombination. It can be applied for spectroscopic analysis in materials science of semicondutors.

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