scholarly journals Second-harmonic imaging microscopy for time-resolved investigations of transition metal dichalcogenides

2020 ◽  
Vol 32 (48) ◽  
pp. 485901
Author(s):  
J E Zimmermann ◽  
B Li ◽  
J C Hone ◽  
U Höfer ◽  
G Mette
Keyword(s):  
Transition Metal ◽  
Second Harmonic ◽  
Transition Metal Dichalcogenides ◽  
Harmonic Imaging ◽  
Time Resolved ◽  
Metal Dichalcogenides

scholarly journals Second-harmonic generation enhancement in monolayer transition-metal dichalcogenides by using an epsilon-near-zero substrate

2021 ◽  
Vol 3 (1) ◽  
pp. 272-278
Author(s):  
Pilar G. Vianna ◽  
Aline dos S. Almeida ◽  
Rodrigo M. Gerosa ◽  
Dario A. Bahamon ◽  
Christiano J. S. de Matos
Keyword(s):  
Dielectric Constant ◽  
Transition Metal ◽  
Harmonic Generation ◽  
Nonlinear Effect ◽  
Second Harmonic ◽  
2D Materials ◽  
Transition Metal Dichalcogenides ◽  
Transition Metal Dichalcogenide ◽  
Metal Dichalcogenides ◽  
Epsilon Near Zero

The scheme illustrates a monolayer transition-metal dichalcogenide on an epsilon-near-zero substrate. The substrate near-zero dielectric constant is used as the enhancement mechanism to maximize the SHG nonlinear effect on monolayer 2D materials.

scholarly journals Optically initialized robust valley-polarized holes in monolayer WSe2

2015 ◽  
Vol 6 (1) ◽  
Author(s):  
Wei-Ting Hsu ◽  
Yen-Lun Chen ◽  
Chang-Hsiao Chen ◽  
Pang-Shiuan Liu ◽  
Tuo-Hung Hou ◽  
...  
Keyword(s):  
Transition Metal ◽  
Low Temperatures ◽  
Room Temperature ◽  
Optical Pumping ◽  
Transition Metal Dichalcogenides ◽  
Kerr Rotation ◽  
Time Resolved ◽  
Recombination Lifetime ◽  
Valley Polarization ◽  
Metal Dichalcogenides

Abstract A robust valley polarization is a key prerequisite for exploiting valley pseudospin to carry information in next-generation electronics and optoelectronics. Although monolayer transition metal dichalcogenides with inherent spin–valley coupling offer a unique platform to develop such valleytronic devices, the anticipated long-lived valley pseudospin has not been observed yet. Here we demonstrate that robust valley-polarized holes in monolayer WSe2 can be initialized by optical pumping. Using time-resolved Kerr rotation spectroscopy, we observe a long-lived valley polarization for positive trion with a lifetime approaching 1 ns at low temperatures, which is much longer than the trion recombination lifetime (∼10–20 ps). The long-lived valley polarization arises from the transfer of valley pseudospin from photocarriers to resident holes in a specific valley. The optically initialized valley pseudospin of holes remains robust even at room temperature, which opens up the possibility to realize room-temperature valleytronics based on transition metal dichalcogenides.

scholarly journals Probing valley population imbalance in transition metal dichalcogenides via temperature-dependent second harmonic generation imaging

2021 ◽  
Vol 5 (1) ◽  
Author(s):  
Leonidas Mouchliadis ◽  
Sotiris Psilodimitrakopoulos ◽  
George Miltos Maragkakis ◽  
Ioanna Demeridou ◽  
George Kourmoulakis ◽  
...  
Keyword(s):  
Transition Metal ◽  
Second Harmonic ◽  
Polarization State ◽  
Transition Metal Dichalcogenides ◽  
Real Space ◽  
Intense Laser ◽  
Additional Degree ◽  
Metal Dichalcogenides ◽  
Population Imbalance ◽  
Scanning Imaging

AbstractDegenerate minima in momentum space—valleys—provide an additional degree of freedom that can be used for information transport and storage. Notably, such minima naturally exist in the band structure of transition metal dichalcogenides (TMDs). When these atomically thin crystals interact with intense laser light, the second harmonic generated (SHG) field inherits special characteristics that reflect not only the broken inversion symmetry in real space but also the valley anisotropy in reciprocal space. The latter is present whenever there exists a valley population imbalance (VPI) between the two valleys and affects the polarization state of the detected SHG. In this work, it is shown that the temperature-induced change of the SHG intensity dependence on the excitation field polarization is a fingerprint of VPI in TMDs. In particular, pixel-by-pixel VPI mapping based on polarization-resolved raster-scanning imaging microscopy was performed inside a cryostat to generate the SHG contrast in the presence of VPI from every point of a TMD flake. The generated contrast is marked by rotation of the SHG intensity polar diagrams at low temperatures and is attributed to the VPI-induced SHG.

Second-Harmonic Spectroscopy for Defects Engineering Monitoring in Transition Metal Dichalcogenides

2018 ◽  
Vol 6 (5) ◽  
pp. 1701327 ◽  
Author(s):  
Henrique G. Rosa ◽  
Lu Junpeng ◽  
Lídia C. Gomes ◽  
Manuel J. L. F. Rodrigues ◽  
Sow Chorng Haur ◽  
...  
Keyword(s):  
Transition Metal ◽  
Second Harmonic ◽  
Transition Metal Dichalcogenides ◽  
Metal Dichalcogenides ◽  
Engineering Monitoring

Edge effects in second-harmonic generation in nanoscale layers of transition-metal dichalcogenides

2015 ◽  
Vol 49 (6) ◽  
pp. 791-796 ◽  
Author(s):  
E. D. Mishina ◽  
N. E. Sherstyuk ◽  
A. P. Shestakova ◽  
S. D. Lavrov ◽  
S. V. Semin ◽  
...  
Keyword(s):  
Transition Metal ◽  
Second Harmonic Generation ◽  
Harmonic Generation ◽  
Edge Effects ◽  
Second Harmonic ◽  
Transition Metal Dichalcogenides ◽  
Metal Dichalcogenides

Second harmonic generation in two-dimensional transition metal dichalcogenides with growth and post-synthesis defects

2D Materials ◽  
2020 ◽  
Vol 7 (4) ◽  
pp. 045020
Author(s):  
William Murray ◽  
Michael Lucking ◽  
Ethan Kahn ◽  
Tianyi Zhang ◽  
Kazunori Fujisawa ◽  
...  
Keyword(s):  
Transition Metal ◽  
Second Harmonic Generation ◽  
Harmonic Generation ◽  
Second Harmonic ◽  
Transition Metal Dichalcogenides ◽  
Two Dimensional ◽  
Metal Dichalcogenides ◽  
Post Synthesis
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