Classical Emergence of Intrinsic Spin-Orbit Interaction of Light at the Nanoscale

Traditionally, in macroscopic geometrical optics intrinsic polarization and spatial degrees of freedom of light can be treated independently. However, at the subwavelength scale these properties appear to be coupled together, giving rise to the spin-orbit interaction (SOI) of light. In this work we address theoretically the classical emergence of the optical SOI at the nanoscale. By means of a full-vector analysis involving spherical vector waves we show that the spin-orbit factorizability condition, accounting the mutual influence between the amplitude (spin) and phase (orbit), is fulfilled only in the far-field limit. On the other side, in the near-field region, an additional relative phase introduces an extra term that hinders the factorization and reveals an intricate dynamical behavior according to the SOI regime. As a result, we find a suitable theoretical framework able to capture analytically the main features of intrinsic SOI of light. Besides allowing for a better understanding into the mechanism leading to its classical emergence at the nanoscale, our approach may be useful in order to design experimental setups that enhance the response of SOI-based effects.Comment: 10 pages, 5 figure

Near-Field Directionality Beyond the Dipole Approximation: Electric Quadrupole and Higher-Order Multipole Angular Spectra

Within the context of spin-related optical phenomena, the near-field directionality is generally understood from the quantum spin Hall effect of light, according to which the transverse spin of surface or guided modes is locked to the propagation direction. So far, most previous works have been focused on the spin properties of circularly polarized dipolar sources. However, in near-field optics, higher-order multipole sources (e.g., quadrupole, octupole, and so on) might become relevant, so a more in-depth formulation would be highly valuable. Building on the angular spectrum representation, we provide a general, analytical, and ready-to-use treatment in order to address the near-field directionality of any multipole field, particularizing to the electric quadrupole case. Besides underpinning and upgrading the current framework on spin-dependent directionality, our results may open up new perspectives for engineering light-matter coupling at the nanoscale.Comment: 7 pages, 2 figures. Supplemental Material (19 pages). Supplemental tools (calculator of angular spectra and animation) available at https://doi.org/10.5281/zenodo.267790

Incandescent temporal metamaterials

Regarded as a promising alternative to spatially shaping matter, time-varying media can be seized to control and manipulate wave phenomena, including thermal radiation. Here, based upon the framework of macroscopic quantum electrodynamics, we elaborate a comprehensive quantum theoretical formulation that lies the basis for investigating thermal emission effects in time-modulated media. Our theory unveils new physics brought about by time-varying media: nontrivial correlations between thermal fluctuating currents at different frequencies and positions, thermal radiation overcoming the black-body spectrum, and quantum vacuum amplification effects at finite temperature. We illustrate how these features lead to striking phenomena and novel thermal emitters, specifically, showing that the time-modulation releases strong field fluctuations confined within epsilon-near-zero (ENZ) bodies, and that, in turn, it enables a narrowband (partially coherent) emission spanning the whole range of wavevectors, from near to far-field regimes.Comment: Main text (11 pages, 5 figures) + Supplementary Information (32 pages

Toward Chiral Sensing and Spectroscopy Enabled by All-Dielectric Integrated Photonic Waveguides

This is the peer reviewed version of the following article: Vázquez-Lozano, J. E., Martínez, A., Toward Chiral Sensing and Spectroscopy Enabled by All-Dielectric Integrated Photonic Waveguides. Laser & Photonics Reviews 2020, 14, 1900422, which has been published in final form at https://doi.org/10.1002/lpor.201900422. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving.[EN] Chiral spectroscopy is a powerful technique enabling to identify optically the chirality of matter. So far, most experiments to check the chirality of matter or nanostructures have been performed through arrangements wherein both the optical excitation and detection are realized via circularly polarized light propagating in free space. However, for the sake of miniaturization, it would be desirable to perform chiral spectroscopy in photonic integrated platforms, with the additional benefit of massive parallel detection, low¿cost production, repeatability, and portability. Here it is shown that all¿dielectric photonic waveguides can support chiral modes under proper combination of fundamental eigenmodes. Two mainstream configurations are investigated: a dielectric wire with square cross section and a slotted waveguide. Three different scenarios in which such waveguides could be used for chiral detection are numerically analyzed: waveguides as near¿field probes, evanescent¿induced chiral fields, and chiroptical interaction in void slots. In all the cases, a metallic nanohelix is considered as a chiral probe, though all the approaches can be extended to other kinds of chiral nanostructures as well as matter. These results establish that chiral applications such as sensing and spectroscopy could be realized in standard integrated optics, in particular, with silicon-based technology.The authors thank S. Lechago for valuable comments and technical support with the numerical simulations. This work was partially supported by funding from the European Commission Project THOR H2020-EU-829067. A.M. also acknowledges funding from Generalitat Valenciana (Grant No. PROMETEO/2019/123) and Spanish Ministry of Science, Innovation and Universities (Grant No. PRX18/00126).Vázquez-Lozano, JE.; Martínez Abietar, AJ. (2020). Toward Chiral Sensing and Spectroscopy Enabled by All-Dielectric Integrated Photonic Waveguides. Laser & Photonics Review. 14(9):1-12. https://doi.org/10.1002/lpor.201900422S112149FDA’S policy statement for the development of new stereoisomeric drugs. (1992). Chirality, 4(5), 338-340. doi:10.1002/chir.530040513Hutt, A. J., & Tan, S. C. (1996). 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Spin resonance under topological driving fields

We study the dynamics of a localized spin-1/2 driven by a time-periodic magnetic field that undergoes a topological transition. Despite the strongly non-adiabatic effects dominating the spin dynamics, we find that the field's topology appears clearly imprinted in the Floquet spin states through an effective Berry phase emerging in the quasienergy. This has remarkable consequences on the spin resonance condition suggesting a whole new class of experiments to spot topological transitions in the dynamics of spins and other two-level systems, from nuclear magnetic resonance to strongly-driven superconducting qubits.España, Ministerio de Economía, Industria y Competitividad FIS2014-53385-

A correlative biomarker study and integrative prognostic model in chemotherapy-naïve metastatic castration-resistant prostate cancer treated with enzalutamide

There is a considerable need to incorporate biomarkers of resistance to new antiandrogen agents in the management of castration-resistant prostate cancer (CRPC). We conducted a phase II trial of enzalutamide in first-line chemo-naïve asymptomatic or minimally symptomatic mCRPC and analyzed the prognostic value of TMPRSS2-ERG and other biomarkers, including circulating tumor cells (CTCs), androgen receptor splice variant (AR-V7) in CTCs and plasma Androgen Receptor copy number gain (AR-gain). These biomarkers were correlated with treatment response and survival outcomes and developed a clinical-molecular prognostic model using penalized cox-proportional hazard model. This model was validated in an independent cohort. Ninety-eight patients were included. TMPRSS2-ERG fusion gene was detected in 32 patients with no differences observed in efficacy outcomes. CTC detection was associated with worse outcome and AR-V7 in CTCs was associated with increased rate of progression as best response. Plasma AR gain was strongly associated with an adverse outcome, with worse median prostate specific antigen (PSA)-PFS (4.2 vs. 14.7 m; p < 0.0001), rad-PFS (4.5 vs. 27.6 m; p < 0.0001), and OS (12.7 vs. 38.1 m; p < 0.0001). The clinical prognostic model developed in PREVAIL was validated (C-Index 0.70) and the addition of plasma AR (C-Index 0.79; p < 0.001) increased its prognostic ability. We generated a parsimonious model including alkaline phosphatase (ALP); PSA and AR gain (C-index 0.78) that was validated in an independent cohort. TMPRSS2-ERG detection did not correlate with differential activity of enzalutamide in first-line mCRPC. However, we observed that CTCs and plasma AR gain were the most relevant biomarkers

Carbon dioxide (CO2) emissions and adherence to Mediterranean diet in an adult population: the Mediterranean diet index as a pollution level index

Background Research related to sustainable diets is is highly relevant to provide better understanding of the impact of dietary intake on the health and the environment. Aim To assess the association between the adherence to an energy-restricted Mediterranean diet and the amount of CO2 emitted in an older adult population. Design and population Using a cross-sectional design, the association between the adherence to an energy-reduced Mediterranean Diet (erMedDiet) score and dietary CO2 emissions in 6646 participants was assessed. Methods Food intake and adherence to the erMedDiet was assessed using validated food frequency questionnaire and 17-item Mediterranean questionnaire. Sociodemographic characteristics were documented. Environmental impact was calculated through greenhouse gas emissions estimations, specifically CO2 emissions of each participant diet per day, using a European database. Participants were distributed in quartiles according to their estimated CO2 emissions expressed in kg/day: Q1 (= 2.80 kg CO2). Results More men than women induced higher dietary levels of CO2 emissions. Participants reporting higher consumption of vegetables, fruits, legumes, nuts, whole cereals, preferring white meat, and having less consumption of red meat were mostly emitting less kg of CO2 through diet. Participants with higher adherence to the Mediterranean Diet showed lower odds for dietary CO2 emissions: Q2 (OR 0.87; 95%CI: 0.76-1.00), Q3 (OR 0.69; 95%CI: 0.69-0.79) and Q4 (OR 0.48; 95%CI: 0.42-0.55) vs Q1 (reference). Conclusions The Mediterranean diet can be environmentally protective since the higher the adherence to the Mediterranean diet, the lower total dietary CO2 emissions. Mediterranean Diet index may be used as a pollution level index

Dairy product consumption and changes in cognitive performance: two-year analysis of the PREDIMED-Plus Cohort

Scope: Dairy consumption has been suggested to impact cognition; however, evidence is limited and inconsistent. This study aims to longitudinally assess the association between dairy consumption with cognitive changes in an older Spanish population at high cardiovascular disease risk. Methods and results: Four thousand six hundred sixty eight participants aged 55–75 years, completed a validated food frequency questionnaire at baseline and a neuropsychological battery of tests at baseline and 2-year follow-up. Multivariable linear regression models are used, scaled by 100 (i.e., the units of β correspond to 1 SD/100), to assess associations between baseline tertile daily consumption and 2-year changes in cognitive performance. Participants in the highest tertile of total milk and whole-fat milk consumption have a greater decline in global cognitive function (β: –4.71, 95% CI: –8.74 to –0.69, p-trend = 0.020 and β: –6.64, 95% CI: –10.81 to –2.47, p-trend = 0.002, respectively) compared to those in the lowest tertile. No associations are observed between low fat milk, yogurt, cheese or fermented dairy consumption, and changes in cognitive performance. Conclusion:Results suggest there are no clear prospective associations between consumption of most commonly consumed dairy products and cognition, although there may be an association with a greater rate of cognitive decline over a 2-year period in older adults at high cardiovascular disease risk for whole-fat milk