Enhancement of spin-orbit interaction and nearly perfect spin-conversion by 1D photonic crystal with the anisotropic defect layer

Although photon spin-orbit interaction (SOI) has been extensively studied, the vortex-conversion efficiency and the enhancement of spin Hall effect in abnormal modes in SOI remain to be investigated. Using an one-dimensional (1D) photonic crystal (PhC) system with the anisotropic defect layer(ADL), we firstly find that the generation efficiency of the vortex beam is close to 50\% when the number of periodic layers of the PhC reaches 5. Secondly, We also discussed the case where linearly polarized light is obliquely incident on a defect state system, and find that the destructive interference between the normal mode and the abnormal mode reaches the maximum, resulting in the enhancement of the spin hall displacement, and the effect can be enhanced at any angle of incidence in this system. Finally, we found that in the defect mode, the mutual conversion of normal and abnormal mode spins can be regulated, and the conversion efficiency can be close to 100\%

Dual-polarization huge photonic spin Hall shift and deep-subwavelength sensing based on topological singularities in one-dimensional photonic crystals

Although several efforts have been taken to enhance the photonic spin Hall shift in deep-subwavelength region, according to effective medium theory, the fundamental confliction between near-zero reflection coefficient and near-zero incident angle still hinders the further application. Here, we reveal a fundamental breakdown of effective medium theory due to the existing of topological singularity in deep-subwavelength region in one-dimensional photonic crystals. We find that near the topological singularity, huge photonic spin Hall shift can be achieved for s-polarization and p-polarization. At the topological singularity, the reflected filed is split as dipole-like distribution with zero photonic spin Hall shift for both-polarizations, which is resulted from the interfere of the spin-maintained normal light and spin-flipped abnormal light. Based on the theoretical research, dual-polarizations thickness and dielectric constant sensing devices can be designed in deep-subwavelength region. Further more, by applying more complicated layered structure, multi-channels dual-polarizations detection and broadband dual-polarizations huge spin Hall shift platform can be designed. This work paves the way to exploring the topological properties and polarization control of photonic crystals and provides a prospective method for the design of multi-channels sensitive detection spin optical devices

The most likely high risk clusters of HFMD cases detected using the purely spatial analysis.

<p>The most likely high risk clusters of HFMD cases detected using the purely spatial analysis.</p

The detected spatial-temporal clusters of HFMD in Shandong Province during 2007 to 2011, and the distribution of HFMD pathogens within these clusters.

<p>Each pie shows the proportion of different HFMD pathogen for each spatial-temporal cluster, but no pathogen data in 2007.</p

Social-demographic characteristics of HFMD cases and the pathogen types of some cases in Shandong Province, 2007–2011.

<p>Social-demographic characteristics of HFMD cases and the pathogen types of some cases in Shandong Province, 2007–2011.</p

The results of the spatial autocorrelation test on HFMD cases in Shandong Province, 2007–2011.

<p>The results of the spatial autocorrelation test on HFMD cases in Shandong Province, 2007–2011.</p

The location of study area, Shandong Province in China.

<p>The location of study area, Shandong Province in China.</p

Annual incidence rates of HFMD in 0–5 years old children (/100,000) per county in Shandong Province, 2007–2011.

<p>Annual incidence rates of HFMD in 0–5 years old children (/100,000) per county in Shandong Province, 2007–2011.</p

The spatial-temporal high risk clusters of HFMD cases detected using Space-Time Permutation model, 2007–2011.

#<p>:‘1’ represents ‘Most likely cluster’; ‘2–7’ represent six ‘Secondary clusters’.</p

Monthly distribution of HFMD cases (0–5 years), 2007–2011.

<p>Monthly distribution of HFMD cases (0–5 years), 2007–2011.</p