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Atomistic Electrodynamics-Quantum Mechanical Framework for Characterizing, Manipulating and Optimizing Nonlinear Optical Processes in 2D Materials

Periodic Reporting for period 1 - ELECTROQUANTUM-2D (Atomistic Electrodynamics-Quantum Mechanical Framework for Characterizing, Manipulating and Optimizing Nonlinear Optical Processes in 2D Materials)

Reporting period: 2018-01-15 to 2020-01-14

We aim at developing atomistic electromagnetic (EM)-quantum mechanical (QM) theoretical models and implementing them in high-performance computing software for characterizing, manipulating, and optimizing linear and nonlinear optical responses of QM emitters/scatterers (including atoms, molecules, quantum dots, and 2D materials) in arbitrary inhomogeneous EM environment.

The main objectives of this ambitious project are: (1) To develop a macroscopic EM approach for simulating optical response from arbitrary nanostructures. (2) To develop an atomistic EM-QM framework for modeling the interaction between the QM emitters/scatterers and classical EM nanostructures. (3) To develop user-friendly and reliable high-performance computing software that seamlessly integrates and implements the theoretical models. (4) Using the software and theoretical models, emerging applications of the QM emitters/scatterers, especially for 2D materials, will be investigated.

The project has high impact on: (1) advances in the science, technology, and industry of Europe; (2) applicant’s future career development; (3) research, industrial, and transferrable knowledge exchange between the host and applicant; (4) design and commercialization of QM devices; (5) training of students and researchers in several interdisciplinary disciplines.
1. During the project we developed the vector potential-scalar potential (A-Phi) framework of Maxwell’s equations and corresponding numerical techniques, including perfectly matched layer, pure scattered field technique, material treatment, near-to-far-field transformation. The near-field and far-field information, such as scattering field pattern and extinction cross section of a nanostructure made of arbitrary materials (lossy and dispersive, lossless, anisotropic) has been generated. The gauge invariance in inhomogeneous EM environment under different gauge conditions (simple, generalized Lorenz gauge, and others) has been numerically demonstrated.

2. The project has established the atomistic EM-QM framework to model the interaction between QM emitters/scatterers and classical EM nanostructures. The population inversion and polarization of the QM emitters/scatterers with arbitrary energy levels could be simulated. The numerical demonstrations for breaking the electric-dipole approximation, rotating-wave approximation, and no back-action approximation in traditional quantum optics theory have been presented. The temporal and spatial dynamics of QM emitters/scatterers and EM fields were studied in free space, resonant cavities, and plasmonic nanostructures. The strong coupling between the QM emitters/scatterers and classical EM nanostructures has been simulated.

3. The nonlinear spin-orbital coupling in metals and 2D materials and corresponding structured light applications have been investigated.
1. Going beyond solving the E-H framework of Maxwell’s equations, as part of this project we developed the vector potential-scalar potential (A-Phi) framework of Maxwell’s equations and corresponding numerical techniques, which allows for simple, accurate, and seamless connections to quantum physics.

2. Going beyond the electric-dipole approximation, rotating-wave approximation, and no back-action approximation in the traditional quantum optics theory, we solved self-consistently and rigorously the coupled A-Phi equations for EM and optical Bloch equation for QM. The spatial and temporal multiscale issues were also overcome by newly proposed numerical schemes.

3. Going beyond the gauge invariance in EM theory, we numerically demonstrated the gauge invariance in arbitrary inhomogeneous EM environment.

4. Regarding the impact of the project, due to the research experience gained in the UK and research work on quantum EM, Dr. Sha has got the opportunity to become Associate Editor of IEEE Access journal (impact factor larger than 4), also secured a highly competitive National Science Foundation of China fund, and got an Assistant Professor position at Zhejiang University (one of top 5 universities in China). Also, the developed solver can be used by the academic community, enterprises, and institutions in Europe and worldwide, which will strengthen and advance Europe’s leading positions in nonlinear optics, low-dimensional materials, quantum physics, and related disciplines. The fellowship also opens up a new and exciting way to initiate collaborations between Dr Sha’s university/group and universities/groups in Europe, which contributed to his engagement visits and conference attendances.
publications for journals and conferences