No abstract

Here, we introduce the first experimental proof of coherent oscillation and coupling of photoswitchable molecules embedded randomly in a polymeric matrix and acting cooperatively upon illumination with UV light. In particular, we demonstrate the specular reflection and Brewster phenomenon alteration of photochromic molecular dipole antennas. We successfully demonstrate the concept of Brewster wavelength, which is based on the dipolar interaction between radiating dipoles and the surrounding matrix possessing a net dipole moment, as a key tool for highly localized sensing of matrix polarity. We also introduce the concept of 'tailored molecular photonic coupling' while highlighting the role of interferences for the design of optically active media by adjusting the photonic response of the medium with the real and imaginary refractive index of photoswitchable molecules in the 'ON' state. Our results enhance our fundamental understanding of coherent dipole radiation and open a new vein of research based on glassy disordered dipolar composites that act as macroscopic antenna with cooperative action; furthermore, these results have important implications for new design rules of tailored photonics.

An optically driven metamaterial with a photoswitchable weak and strong molecular‐plasmonic coupling is demonstrated. In this active perfect absorber, the absorption band can be broadened more than 150 nm (split with an energy difference of 780 meV) by UV irradiation, which demonstrates a new class of optically tunable metamaterial absorber for visible frequencies.

The study aims at investigating the satisfaction level and attitudes of undergraduate students at United Arab Emirates University towards eLearning and virtual classes in exceptional circumstances of COVID-19 Crisis, in view of five demographic independent variables: students' gender, educational level, residential location, college, and GPA. The researchers adopted and implemented a questionnaire where its validity and reliability for collecting data have been verified. Mean, standard deviations, and one-way ANOVA tests were conducted. The results indicate that the students' satisfaction level and attitudes towards eLearning and virtual classes are strong in general with varying degrees between items. The results did not show a significant difference at the level (α = 0.05) for the independent variables: students' gender, residential location, college, and GPA. However, the results imply that there is a statistically significant difference in students' satisfaction level and attitudes towards eLearning and virtual classes for the independent variable of educational level. The study concluded with few recommendations; supporting the current efforts of the university to provide all the requirements of education via eLearning and virtual classes such as suitable infrastructure and technical support. Besides, there is a need for a continuous update of the teaching and learning platforms in line with continuous development and training for instructors and students.