Laser Control of Resonance Tunneling via an Exceptional Point

2020 ◽  
Vol 124 (25) ◽  
Author(s):  
Anael Ben-Asher ◽  
Daniel Šimsa ◽  
Tereza Uhlířová ◽  
Milan Šindelka ◽  
Nimrod Moiseyev
2000 ◽  
Vol 631 ◽  
Author(s):  
J. G. Fleming ◽  
E. Chow ◽  
S.-Y. Lin

ABSTRACTResonance Tunneling Diodes (RTDs) are devices that can demonstrate very highspeed operation. Typically they have been fabricated using epitaxial techniques and materials not consistent with standard commercial integrated circuits. We report here the first demonstration of SiO2-Si-SiO2 RTDs. These new structures were fabricated using novel combinations of silicon integrated circuit processes.


2021 ◽  
Vol 920 ◽  
Author(s):  
Abdulla Ghani ◽  
Wolfgang Polifke
Keyword(s):  

Abstract


2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Arik Bergman ◽  
Robert Duggan ◽  
Kavita Sharma ◽  
Moshe Tur ◽  
Avi Zadok ◽  
...  

AbstractThe exotic physics emerging in non-Hermitian systems with balanced distributions of gain and loss has recently drawn a great deal of attention. These systems exhibit phase transitions and exceptional point singularities in their spectra, at which eigen-values and eigen-modes coalesce and the overall dimensionality is reduced. So far, these principles have been implemented at the expense of precise fabrication and tuning requirements, involving tailored nano-structured devices with controlled optical gain and loss. In this work, anti-parity-time symmetric phase transitions and exceptional point singularities are demonstrated in a single strand of single-mode telecommunication fibre, using a setup consisting of off-the-shelf components. Two propagating signals are amplified and coupled through stimulated Brillouin scattering, enabling exquisite control over the interaction-governing non-Hermitian parameters. Singular response to small-scale variations and topological features arising around the exceptional point are experimentally demonstrated with large precision, enabling robustly enhanced response to changes in Brillouin frequency shift.


Micromachines ◽  
2021 ◽  
Vol 12 (4) ◽  
pp. 426
Author(s):  
Yang Liu ◽  
Pengyun Yan ◽  
Feng Liu ◽  
Aoqun Jian ◽  
Shengbo Sang

Inspired by exceptional point (EP) sensing in non-Hermitian systems, in this work, a label-free biosensor for detecting low-concentration analytes is proposed, via a special multilayer structure: a resonant optical tunneling resonator. Due to the square root topology near the exceptional point, a recognized target analyte perturbs the system deviated from the exceptional point, leading to resolvable modes splitting in the transmission spectrum. The performance of the designed sensor is analyzed by the coupled-mode theory and transfer matrix method, separately. Here, the simulation results demonstrate that the obtained sensitivity is 17,120 nm/imaginary part unit of refractive index (IP) and the theoretical detection limit is 4.2 × 10−8 IP (regarding carcinoembryonic antigen (CEA), the minimum detection value is 1.78 ng). Instead of the typical diffusion manner, the liquid sample is loaded by convection, which can considerably improve the efficiency of sample capture and shorten the response time of the sensor. The sketched sensor may find potential application in the fields of biomedical detection, environment protection, and drinking water safety.


Symmetry ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 205
Author(s):  
Dietrich Haase ◽  
Gunter Hermann ◽  
Jörn Manz ◽  
Vincent Pohl ◽  
Jean Christophe Tremblay

Quantum simulations of the electron dynamics of oriented benzene and Mg-porphyrin driven by short (<10 fs) laser pulses yield electron symmetry breaking during attosecond charge migration. Nuclear motions are negligible on this time domain, i.e., the point group symmetries G = D6h and D4h of the nuclear scaffolds are conserved. At the same time, the symmetries of the one-electron densities are broken, however, to specific subgroups of G for the excited superposition states. These subgroups depend on the polarization and on the electric fields of the laser pulses. They can be determined either by inspection of the symmetry elements of the one-electron density which represents charge migration after the laser pulse, or by a new and more efficient group-theoretical approach. The results agree perfectly with each other. They suggest laser control of symmetry breaking. The choice of the target subgroup is restricted, however, by a new theorem, i.e., it must contain the symmetry group of the time-dependent electronic Hamiltonian of the oriented molecule interacting with the laser pulse(s). This theorem can also be applied to confirm or to falsify complementary suggestions of electron symmetry breaking by laser pulses.


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