The Experts below are selected from a list of 318 Experts worldwide ranked by ideXlab platform
Lifa Zhang - One of the best experts on this subject based on the ideXlab platform.
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chiral phonons in the indirect Optical Transition of a mos 2 ws 2 heterostructure
Physical Review B, 2020Co-Authors: Wei Zhang, Ajit Srivastava, Lifa ZhangAbstract:Since experimental verification of the predicted chiral phonon (CP), CPs have become a rising topic. The previous observation was a two-step process, which identified the CP by intervalley transfer of valley holes created from direct Optical Transition. It is highly desirable to simplify the creation and detection of CPs. Moreover, while indirect Optical Transition in Transition metal dichalcogenide heterostructures has been observed, it is important to promote the understanding of the interplay between the phonon, electron, and photon in the indirect Transition. Here, we take the ${\mathrm{MoS}}_{2}$/${\mathrm{WS}}_{2}$ heterostructure as a prototype and study CPs in the indirect Optical Transition. By first-principles calculations, the heterostructure with an indirect electronic gap exhibits CPs at the high-symmetry $\ifmmode\pm\else\textpm\fi{}\mathbit{K}$ points of the phonon Brillouin zone, which have sizable circular polarization and discrete pseudoangular momentum. CPs with distinct chiralities can be selectively and directly generated in indirect Optical Transitions by tuning the Optical chirality and frequency. These findings provide microscopic understanding of the indirect Optical Transition by interacting chiral fermions and chiral bosons and enable more convenient detection and control of CPs.
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Chiral phonons in the indirect Optical Transition of a MoS 2 / WS 2 heterostructure
Physical Review B, 2020Co-Authors: Wei Zhang, Ajit Srivastava, Lifa ZhangAbstract:Since experimental verification of the predicted chiral phonon (CP), CPs have become a rising topic. The previous observation was a two-step process, which identified the CP by intervalley transfer of valley holes created from direct Optical Transition. It is highly desirable to simplify the creation and detection of CPs. Moreover, while indirect Optical Transition in Transition metal dichalcogenide heterostructures has been observed, it is important to promote the understanding of the interplay between the phonon, electron, and photon in the indirect Transition. Here, we take the ${\mathrm{MoS}}_{2}$/${\mathrm{WS}}_{2}$ heterostructure as a prototype and study CPs in the indirect Optical Transition. By first-principles calculations, the heterostructure with an indirect electronic gap exhibits CPs at the high-symmetry $\ifmmode\pm\else\textpm\fi{}\mathbit{K}$ points of the phonon Brillouin zone, which have sizable circular polarization and discrete pseudoangular momentum. CPs with distinct chiralities can be selectively and directly generated in indirect Optical Transitions by tuning the Optical chirality and frequency. These findings provide microscopic understanding of the indirect Optical Transition by interacting chiral fermions and chiral bosons and enable more convenient detection and control of CPs.
Wei-bo Gao - One of the best experts on this subject based on the ideXlab platform.
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Coherent control of a strongly driven silicon vacancy Optical Transition in diamond
Nature Communications, 2017Co-Authors: Yu Zhou, Abdullah Rasmita, Ke Li, Qihua Xiong, Igor Aharonovich, Wei-bo GaoAbstract:The ability to prepare, Optically read out and coherently control single quantum states is a key requirement for quantum information processing. Optically active solid-state emitters have emerged as promising candidates with their prospects for on-chip integration as quantum nodes and sources of coherent photons connecting these nodes. Under a strongly driving resonant laser field, such quantum emitters can exhibit quantum behaviour such as Autler–Townes splitting and the Mollow triplet spectrum. Here we demonstrate coherent control of a strongly driven Optical Transition in silicon vacancy centre in diamond. Rapid Optical detection of photons enabled the observation of time-resolved coherent Rabi oscillations and the Mollow triplet spectrum. Detection with a probing Transition further confirmed Autler–Townes splitting generated by a strong laser field. The coherence time of the emitted photons is comparable to its lifetime and robust under a very strong driving field, which is promising for the generation of indistinguishable photons. Silicon vacancy centres in diamond have been identified as potential highly efficient solid-state qubits for on-chip integration. Here, Zhou et al . demonstrate coherent control of silicon vacancy centres in nanodiamonds and observe Autler-Townes splitting, Mollow triplet and Rabi oscillations.
Taisuke Ozaki - One of the best experts on this subject based on the ideXlab platform.
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Unfolding Optical Transition weights of impurity materials for first-principles LCAO electronic structure calculations
Physical Review B, 2020Co-Authors: Yung-ting Lee, Chi-cheng Lee, Masahiro Fukuda, Taisuke OzakiAbstract:A method to analyze Optical Transitions is developed by combining the Kubo-Greenwood formula with the unfolding method to construct an unfolded electronic band structure with Optical Transition weights, which allows us to investigate how Optical Transitions are perturbed by imperfections such as impurity, vacancy, and structural distortions. Based on the Kubo-Greenwood formula, we first calculate frequency-dependent Optical conductivity based on the first-principles electronic structure calculations using the linear combinations of atomic orbitals. Benefiting from the atomic orbital basis sets, the frequency-dependent Optical conductivity can be traced back to their individual components before summations over all of $k$ points and bands. As a result, Optical Transition weights of the material can be put on the unfolded electronic band structure to show contributions at different $k$ points and bands. This method is especially useful to study the effects of broken symmetry in the Optical Transitions due to presence of impurities in the materials. As a demonstration, decomposed Optical Transition weights of a monolayer Si-doped graphene are shown in the electronic band structure.
Yu Zhou - One of the best experts on this subject based on the ideXlab platform.
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Coherent control of a strongly driven silicon vacancy Optical Transition in diamond
Nature Communications, 2017Co-Authors: Yu Zhou, Abdullah Rasmita, Ke Li, Qihua Xiong, Igor Aharonovich, Wei-bo GaoAbstract:The ability to prepare, Optically read out and coherently control single quantum states is a key requirement for quantum information processing. Optically active solid-state emitters have emerged as promising candidates with their prospects for on-chip integration as quantum nodes and sources of coherent photons connecting these nodes. Under a strongly driving resonant laser field, such quantum emitters can exhibit quantum behaviour such as Autler–Townes splitting and the Mollow triplet spectrum. Here we demonstrate coherent control of a strongly driven Optical Transition in silicon vacancy centre in diamond. Rapid Optical detection of photons enabled the observation of time-resolved coherent Rabi oscillations and the Mollow triplet spectrum. Detection with a probing Transition further confirmed Autler–Townes splitting generated by a strong laser field. The coherence time of the emitted photons is comparable to its lifetime and robust under a very strong driving field, which is promising for the generation of indistinguishable photons. Silicon vacancy centres in diamond have been identified as potential highly efficient solid-state qubits for on-chip integration. Here, Zhou et al . demonstrate coherent control of silicon vacancy centres in nanodiamonds and observe Autler-Townes splitting, Mollow triplet and Rabi oscillations.
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Coherent control of a strongly driven silicon vacancy Optical Transition in diamond
'Springer Science and Business Media LLC', 2017Co-Authors: Yu Zhou, Rasmita Abdullah, Xiong Qihua, Aharonovich Igor, Gao Wei-boAbstract:The ability to prepare, Optically read out and coherently control single quantum states is a key requirement for quantum information processing. Optically active solid state emitters have emerged as promising candidates with their prospects for on chip integration as quantum nodes and sources of coherent photons for connecting these nodes. Under strongly driving resonant laser field, such quantum emitter can exhibit quantum behavior such as Autler-Townes splitting and Mollow triplet spectrum. Here we demonstrate coherent control of a strongly driven Optical Transition in silicon vacancy (SiV) center in diamond. Rapid Optical detection of photons enabled the observation of time resolved coherent Rabi oscillations and the Mollow triplet from an Optical Transition of a single SiV defect. Detection with a probing Transition further confirmed Autler-Townes splitting generated by a strong laser field. Coherence time of the emitted photons is shown to be comparable to its lifetime and robust under very strong driving laser field, which is promising for generation of indistinguishable photons.Comment: updated version with new figure 5.Accepted to nature communication
Stephen K. O’leary - One of the best experts on this subject based on the ideXlab platform.
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Spectral variations in the Optical Transition matrix element and their impact on the Optical properties associated with hydrogenated amorphous silicon
Solid State Communications, 2011Co-Authors: Farida Orapunt, Stephen K. O’learyAbstract:Abstract Using an empirical model for the density of states functions associated with hydrogenated amorphous silicon, in conjunction with an elementary model for the Optical Transition matrix elements, we aim to explore how variations in the matrix elements impact upon the spectral dependence of the Optical properties associated with this material. We also wish to ascertain as to whether or not the hydrogenated amorphous silicon mobility gap result suggested by Jackson et al. [W.B. Jackson, S.M. Kelso, C.C. Tsai, J.W. Allen, S.-J. Oh, Phys. Rev. B 31 (1985) 5187] is consistent with the results of the experiment. We find that the mobility gap value suggested by Jackson et al. is too large. An upper bound on the mobility gap associated with hydrogenated amorphous silicon of 1.68 eV is suggested instead. Electrical measurements performed on undoped hydrogenated amorphous silicon yield a mobility gap value that is consistent with this bound.
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Spectral dependence of the squared average Optical Transition matrix element associated with hydrogenated amorphous silicon
Applied Physics Letters, 2003Co-Authors: Stephen K. O’learyAbstract:Using an empirical model for the density of states functions, in conjunction with an elementary model for the Optical Transition matrix elements, the spectral dependence of the squared average Optical Transition matrix element associated with hydrogenated amorphous silicon was evaluated. It was predicted that this squared average matrix element saturates at and beyond the mobility gap, decreases sharply just below the mobility gap as the photon energy is diminished, and then saturates at sufficiently low photon energies. The value of the squared average Optical Transition matrix element at low photon energies depends on the density of localized electronic states. The results suggest that a careful experimental measurement of the spectral dependence of this matrix element will provide one with a direct means of determining the position of the mobility gap of this semiconductor.
