Tailoring the optical response of metasurfaces by deterministic structural disorder (Conference Presentation)

2018 ◽  
Author(s):  
Isabelle Staude ◽  
Stefan Fasold ◽  
Dennis Arslan ◽  
Aso Rahimzadegan ◽  
Trideep Kawde ◽  
...  
Keyword(s):  
Optical Response ◽  
Structural Disorder

Propagation and Scattering of Exciton-Polaritons in Nitride-Based Multiple Quantum Wells

2000 ◽  
Vol 639 ◽  
Author(s):  
Guillaume Malpuech ◽  
Marian Zamfirescu ◽  
Alexey Kavokin ◽  
Aldo Di Carlo
Keyword(s):  
Elastic Scattering ◽  
Quantum Wells ◽  
Incident Light ◽  
Optical Response ◽  
Structural Disorder ◽  
Multiple Quantum ◽  
Coherent Signal ◽  
Temporal Behaviour ◽  
Exciton Polaritons ◽  
Dark Exciton

ABSTRACTWe show theoretically that disorder-induced scattering of light between « bright » and « dark » exciton-polariton modes governs the coherent optical response of GaN/AlGaN quantum wells (QWs) on a femtosecond scale. The incident light essentially excites the “bright” modes, they emit the most part of light radiatively during first few hundreds of femtoseconds. The rest of the coherent signal, i.e. the temporal behaviour on a scale from 1 to few picoseconds, comes from the “dark” modes, populated due to the elastic scattering processes in the system, and mixed so that they form two bulk-like polariton branches. The pico-second scale optical response of GaN/AlGaN QWs is essentially incoherent because of a very efficient scattering of exciton-polaritons by a structural disorder.

Measurement and Reduction of Radiation Damage in Frozen Hydrated Crystalline Specimens

1978 ◽  
Vol 36 (3) ◽  
pp. 70-77 ◽  
Author(s):  
R.M. Glaeser ◽  
S.B. Hayward
Keyword(s):  
Diffraction Pattern ◽  
Structural Information ◽  
Structural Disorder ◽  
Structural Features ◽  
Biological Macromolecules ◽  
Diffraction Intensity ◽  
Object Structure ◽  
Specimen Material ◽  
Unit Cells ◽  
Identical Unit

Highly ordered or crystalline biological macromolecules become severely damaged and structurally disordered after a brief electron exposure. Evidence that damage and structural disorder are occurring is clearly given by the fading and eventual disappearance of the specimen's electron diffraction pattern. The fading and disappearance of sharp diffraction spots implies a corresponding disappearance of periodic structural features in the specimen. By the same token, there is a oneto- one correspondence between the disappearance of the crystalline diffraction pattern and the disappearance of reproducible structural information that can be observed in the images of identical unit cells of the object structure. The electron exposures that result in a significant decrease in the diffraction intensity will depend somewhat upon the resolution (Bragg spacing) involved, and can vary considerably with the chemical makeup and composition of the specimen material.

Xenon ion irradiation of superconducting YBa2Cu3O7 thin films

1990 ◽  
Vol 48 (4) ◽  
pp. 92-93
Author(s):  
H. Watanabe ◽  
B. Kabius ◽  
B. Roas ◽  
K. Urban
Keyword(s):  
Defect Formation ◽  
Ion Irradiation ◽  
High Resolution Electron Microscopy ◽  
Structural Disorder ◽  
Flux Lines ◽  
Pinning Effect ◽  
Magnetic Flux Lines ◽  
Resolution Electron ◽  
Radiation Induced ◽  
Induced Defects

Recently it was reported that the critical current density(Jc) of YBa2Cu2O7, in the presence of magnetic field, is enhanced by ion irradiation. The enhancement is thought to be due to the pinning of the magnetic flux lines by radiation-induced defects or by structural disorder. The aim of the present study was to understand the fundamental mechanisms of the defect formation in association with the pinning effect in YBa2Cu3O7 by means of high-resolution electron microscopy(HRTEM).The YBa2Cu3O7 specimens were prepared by laser ablation in an insitu process. During deposition, a substrate temperature and oxygen atmosphere were kept at about 1073 K and 0.4 mbar, respectively. In this way high quality epitaxially films can be obtained with the caxis parallel to the <100 > SrTiO3 substrate normal. The specimens were irradiated at a temperature of 77 K with 173 MeV Xe ions up to a dose of 3.0 × 1016 m−2.

The geometric structure and optical response of gaseous endohedral magnesium-fullerenes

2003 ◽  
Vol 50 (15-17) ◽  
pp. 2691-2704 ◽  
Author(s):  
M. Aichinger ◽  
S. A. Chin ◽  
E. Krotscheck ◽  
H. A. Schuessler
Keyword(s):  
Geometric Structure ◽  
Optical Response

A New Method of Viscosity Determination from the Electro-Optical Response of a Nematic LCD

1996 ◽  
Vol 6 (12) ◽  
pp. 1663-1668 ◽  
Author(s):  
O. Cossalter ◽  
B. Cramer ◽  
D. A. Mlynski
Keyword(s):  
Optical Response ◽  
New Method ◽  
Viscosity Determination

A New Fluorescent Salen-uranyl Sensor for the Sub-ppm Detection of Chemical Warfare Agents

2020 ◽  
Vol 24 (20) ◽  
pp. 2378-2382
Author(s):  
Andrea Pappalardo ◽  
Chiara M.A. Gangemi ◽  
Rosa Maria Toscano ◽  
Giuseppe Trusso Sfrazzetto
Keyword(s):  
Real Time ◽  
Fluorescent Sensor ◽  
Chemical Warfare Agents ◽  
Optical Response ◽  
Chemical Warfare ◽  
Lethal Effects ◽  
Strong Affinity ◽  
Chemical Attack ◽  
Fluorescence Measurements ◽  
Warfare Agents

Real-time sensing of Chemical Warfare Agents (CWAs) is today a crucial topic to prevent the lethal effects of a terroristic chemical attack. For this reason, the development of efficient, selective, sensitive and reversible sensoristic devices, able to detect by optical response ppm levels of these compounds, is strongly required. Here, the synthesis of a new fluorescent sensor based on a salen-uranyl scaffold, functionalized with two bodipy moieties, and its application for the detection of sub-ppm levels of CWAs is reported. Detection properties were evaluated by fluorescence measurements and selectivity tests demonstrated the strong affinity for CWAs.

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