Diffraction grating parameter retrieval using non-paraxial structured beams in coherent Fourier scatterometry

In recent years, a lot of works have been published that use parameter retrieval using Orbital Angular Momentum (OAM) beams. Most make use of the OAM of different Laguerre-Gauss modes. However, those specific optical beams are paraxial beams and this limits the regime in which they can be used. In this paper, we report on the first results on retrieving the geometric parameters of a diffraction grating by analysing the corresponding complex-valued (i.e., amplitude and phase) Helmholtz Natural Modes (HNM) spectra containing both the azimuthal (i.e., n) and radial (i.e., m) indices. HNMs are a set of orthogonal, non-paraxial beams with finite energy carrying OAM. We use the coherent Fourier scatterometry (CFS) setup to calculate the field scattered from the diffraction grating. The amplitude and phase contributions of each HNM are then obtained by numerically calculating the overlap integral of the scattered field with the different modes. We show results on the sensitivity of the HNMs to several grating parameters.

2D-Map of Intermolecular Interactions in Organic Chemistry Reveals Underrepresented Area of Research

The molecular orbital (MO) theory is an indispensable model to describe the interaction between two molecular species, particularly during chemical bond formation. Here we show that by plotting the energy difference (E_DA) of the HOMO of an electron donor and the LUMO of an acceptor against their overlap integral (S_DA), many similar types of bimolecular interactions tend to be clustered near one another on the 2D map. Interestingly, in one of the six arbitrarily divided sections designated as “B2”, the interacting molecular pairs appear to present a type of interaction as a “hybrid” between chemical reaction and radical pair formation, a lesser explored area of research. We propose that such interactions could be crucial for the development of materials with unique optical, magnetic, and catalytic properties from purely organic molecules.<br>

2D-Map of Intermolecular Interactions in Organic Chemistry Reveals Underrepresented Area of Research

The molecular orbital (MO) theory is an indispensable model to describe the interaction between two molecular species, particularly during chemical bond formation. Here we show that by plotting the energy difference (E_DA) of the HOMO of an electron donor and the LUMO of an acceptor against their overlap integral (S_DA), many similar types of bimolecular interactions tend to be clustered near one another on the 2D map. Interestingly, in one of the six arbitrarily divided sections designated as “B2”, the interacting molecular pairs appear to present a type of interaction as a “hybrid” between chemical reaction and radical pair formation, a lesser explored area of research. We propose that such interactions could be crucial for the development of materials with unique optical, magnetic, and catalytic properties from purely organic molecules.<br>

COVERED FOUR-PORT REFLECTIVE SPLITTER WITH ZEROTH ORDER CANCELLED

In this paper, the sandwiched configuration is designed under normal incidence with zeroth order eliminated so as to design a highly-efficient four-port output with polarization independence. Through rigorous coupled-wave analysis method, the splitting parameters are calculated to get a good polarization-independence effect, where the four reflective efficiencies are over 20%, respectively. The final findings show that this grating has good diffraction characteristics and high stability in practice. Furthermore, the coupling mechanism of grating can be explained for the cancellation of the zeroth order by studying the overlap integral and the electric field distribution.

Ab initio теория уравнения состояния сжатых кристаллов инертных газов

Nonempirical equations of state of compressed rare gas crystals Ne, Ar, Kr, and Xe are studied on the basis of the earlier-obtained ab initio adiabatic potential. The paired and three-body short-range repulsive potentials are calculated by the Hartree–Fock method in the basis of localized functions with their exact mutual orthogonalization and do not contain experimentally determined parameters. The theory is compared with the experiment and results of calculations by other authors. Analysis of the proposed equations of state for large compressions has shown the importance of taking into account the three-body interaction and the terms of the higher order in the overlap integral in compressed neon and the sufficiency of the quadratic approximation in the orthogonalization of functions in heavy rare gas crystals.

[2.2]Paracyclophane-based single molecular wire consisting of four π-electron systems

A [2.2]paracyclophane-based through-space–conjugated tetramer comprising four partially stacked π-electron systems was designed and synthesized, with a large overlap integral between the photoluminescence spectrum of the terminal π-electron system of the through-space–conjugated trimer and the absorption band of the fourth π-electron system. Efficient unidirectional photoexcited energy transfer in the tetramer occurred by the Förster mechanism; the energy transfer efficiency and related rate constants were found to be >0.999 and >1012 s–1, respectively, and stepwise energy transfer was found to be dominant. The [2.2]paracyclophane-based tetramer acted as a single molecular wire for efficient unidirectional photoexcited energy transfer.