Thermal radiation transferred to the guided modes of optical interference coatings.

An electromagnetic model is developed to predict the thermal radiation which is trapped in a multilayer structure and transferred to its guided modes. The theory is based on the electromagnetic power supplied by the thermal currents given by the fluctuation-dissipation theorem. The source of the radiation is the ambient temperature or that caused by the optical absorption of the component subjected to spatio-temporal illumination. A numerical example is given for a multi-dielectric mirror at thermodynamic equilibrium. It is shown that the thermal radiation transferred to the guided modes of the multilayer can be much larger or lower than the radiation emerging in free space outside the component.

Characterization of the gut bacterial and viral microbiota in latent autoimmune diabetes in adults.

Latent autoimmune diabetes in adults (LADA) is a heterogeneous disease characterized by autoantibodies against insulin producing pancreatic beta cells and initial lack of need for insulin treatment. The aim of the present study was to investigate if individuals with LADA have an altered gut microbiota relative to non-diabetic control subjects, individuals with type 1 diabetes (T1D), and individuals with type 2 diabetes (T2D). Bacterial community profiling was performed with primers targeting the variable region 4 of the 16S rRNA gene and sequenced. Amplicon sequence variants (ASVs) were generated with DADA2 and annotated to the SILVA database. The gut virome was sequenced, using a viral particle enrichment and metagenomics approach, assembled, and quantified to describe the composition of the viral community. Comparison of the bacterial alpha- and beta-diversity measures revealed that the gut bacteriome of individuals with LADA resembled that of individuals with T2D. Yet, specific genera were found to differ in abundance in individuals with LADA compared with T1D and T2D, indicating that LADA has unique taxonomical features. The virome composition reflected the stability of the most dominant order Caudovirales and the families Siphoviridae, Podoviridae, and Inoviridae, and the dominant family Microviridae. Further studies are needed to confirm these findings.

Fetal Overgrowth and Preterm Delivery in Women With Type 1 Diabetes Using Insulin Pumps or Multiple Daily Injections: A Post Hoc Analysis of the EVOLVE Study Cohort.

OBJECTIVE: To compare the risk of fetal overgrowth and preterm delivery in pregnant women with type 1 diabetes (T1D) treated with insulin pumps versus multiple daily injections (MDI) and examine whether possible differences were mediated through improved glycemic control or gestational weight gain during pregnancy. RESEARCH DESIGN AND METHODS: The risk of pregnancy and perinatal outcomes were evaluated in a cohort of 2,003 pregnant women with T1D enrolled from 17 countries in a real-world setting during 2013-2018. RESULTS: In total, 723 women were treated with pumps and 1,280 with MDI. At inclusion (median gestational weeks 8.6 [interquartile range 7-10]), pump users had lower mean HbA1c (mean ± SD 50.6 ± 9.8 mmol/mol [6.8 ± 0.9%] vs. 53.6 ± 13.8 mmol/mol [7.1 ± 1.3%], P < 0.001), longer diabetes duration (18.4 ± 7.8 vs. 14.4 ± 8.2 years, P < 0.001), and higher prevalence of retinopathy (35.3% vs. 24.4%, P < 0.001). Proportions of large for gestational age (LGA) offspring and preterm delivery were 59.0% vs. 52.2% (adjusted odds ratio [OR] 1.36 [95% CI 1.09; 1.70], P = 0.007) and 39.6% vs. 32.1% (adjusted OR 1.46 (95% CI 1.17; 1.82), P < 0.001), respectively. The results did not change after adjustment for HbA1c or gestational weight gain. CONCLUSIONS: Insulin pump treatment in pregnant women with T1D, prior to the widespread use of continuous glucose monitoring or automated insulin delivery, was associated with a higher risk of LGA offspring and preterm delivery compared with MDI in crude and adjusted analyses. This association did not appear to be mediated by differences in glycemic control as represented by HbA1c or by gestational weight gain.

Photo-induced thermal radiation of optical interference coatings submitted to a spatio-temporal illumination.

We present an electromagnetic model for photo-induced thermal radiation in multi-layer interference filters subjected to arbitrary pulsed illumination with limited beam size. Numerical calculation is used to analyze various structures affecting thermal radiation, such as multi-dielectric mirrors in the mid-infrared range. Other zero-admittance structures are shown to strongly confine and enhance the thermal radiation with an emissivity close to unity at pre-defined frequencies (wavelength and angles). Calculation tools are chosen that encourage the use of techniques for synthesizing thin-film multilayers able to control thermal radiation.

Frequency-Dependent Squeezed Vacuum Source for the Advanced Virgo Gravitational-Wave Detector.

In this Letter, we present the design and performance of the frequency-dependent squeezed vacuum source that will be used for the broadband quantum noise reduction of the Advanced Virgo Plus gravitational-wave detector in the upcoming observation run. The frequency-dependent squeezed field is generated by a phase rotation of a frequency-independent squeezed state through a 285 m long, high-finesse, near-detuned optical resonator. With about 8.5 dB of generated squeezing, up to 5.6 dB of quantum noise suppression has been measured at high frequency while close to the filter cavity resonance frequency, the intracavity losses limit this value to about 2 dB. Frequency-dependent squeezing is produced with a rotation frequency stability of about 6 Hz rms, which is maintained over the long term. The achieved results fulfill the frequency dependent squeezed vacuum source requirements for Advanced Virgo Plus. With the current squeezing source, considering also the estimated squeezing degradation induced by the interferometer, we expect a reduction of the quantum shot noise and radiation pressure noise of up to 4.5 dB and 2 dB, respectively.

Congenital malformations among offspring of women with type 1 diabetes who use insulin pumps: a prospective cohort study.

AIMS/HYPOTHESIS: Continuous subcutaneous insulin infusion by insulin pump is often superior in improving glycaemic control compared with conventional multiple daily insulin injection (MDI). However, whether pump treatment leads to improved pregnancy outcomes in terms of congenital malformations and perinatal death remains unknown. The present aim was to evaluate the risk of malformations and perinatal and neonatal death in pregnant women with type 1 diabetes treated with pump or MDI. METHODS: We performed a secondary analysis of a prospective multinational cohort of 2088 pregnant women with type 1 diabetes in a real-world setting who were treated by pump (n=750) or MDI (n=1338). ORs for offspring with congenital malformations or perinatal or neonatal death were calculated using crude data and by logistic regression on propensity score-matched data. RESULTS: At enrolment (gestational week 8; 95% CI 4, 14), pump users had a higher educational level (university degree: 37.3% vs 25.1%; p<0.001) and better glycaemic control (mean HbA1c: 51±10 mmol/mol [6.8±0.9%] vs 54±14 mmol/mol [7.1±1.3%], p<0.001) compared with MDI users. Moreover, a greater proportion of pump users had an HbA1c level below 75 mmol/mol (9%) (97.6% vs 91.9%, p<0.001), and more often reported taking folic acid supplementation (86.3% vs 74.8%; p<0.001) compared with MDI users. All clinically important potential confounders were balanced after propensity score matching, and HbA1c remained lower in pump users. The proportion of fetuses with at least one malformation was 13.5% in pump users vs 11.2% in MDI users (crude OR 1.23; 95% CI 0.94, 1.61; p=0.13; propensity score-matched (adjusted) OR 1.11; 95% CI 0.81, 1.52; p=0.52). The proportion of fetuses with at least one major malformation was 2.8% in pump users vs 3.1% in MDI users (crude OR 0.89; 95% CI 0.52, 1.51; p=0.66; adjusted OR 0.78; 95% CI 0.42, 1.45; p=0.43), and the proportions of fetuses carrying one or more minor malformations (but no major malformations) were 10.7% vs 8.1% (crude OR 1.36; 95% CI 1.00, 1.84; p=0.05; adjusted OR 1.23; 95% CI 0.87, 1.75; p=0.25). The proportions of perinatal and neonatal death were 1.6% vs 1.3% (crude OR 1.23; 95% CI 0.57, 2.67; p=0.59; adjusted OR 2.02; 95% CI 0.69, 5.93; p=0.20) and 0.3% vs 0.3% (n=2 vs n=4, p=not applicable), respectively. CONCLUSIONS/INTERPRETATIONS: Insulin pump treatment was not associated with a lower risk of congenital malformations, despite better glycaemic control in early pregnancy compared with MDI. Further studies exploring the efficacy and safety of pump treatment during pregnancy are needed.

Photo-induced temperature in optical interference coatings.

The photo-induced temperature in multilayer systems is calculated using an original analytical model based on optical/thermal analogies. Various illumination regimes are considered, ranging from ps pulses to a continuous regime, while taking into account a variable repetition rate. The temporal and spatial (3D) resolutions are quantified, and the distributions of temperature and stationary optical field are compared. The temperature spectra are given as a function of the illumination wavelength. Thermal and electromagnetic damage thresholds are compared. Lastly, the thermal fringes resulting from structured optical illumination are studied.

Comparison of treatment with insulin degludec and glargine U100 in patients with type 1 diabetes prone to nocturnal severe hypoglycaemia: The HypoDeg randomized, controlled, open-label, crossover trial.

AIM: To investigate whether the long-acting insulin analogue insulin degludec compared with insulin glargine U100 reduces the risk of nocturnal symptomatic hypoglycaemia in patients with type 1 diabetes (T1D). METHODS: Adults with T1D and at least one episode of nocturnal severe hypoglycaemia during the last 2 years were included in a 2-year prospective, randomized, open, multicentre, crossover trial. A total of 149 patients were randomized 1:1 to basal-bolus therapy with insulin degludec and insulin aspart or insulin glargine U100 and insulin aspart. Each treatment period lasted 1 year and consisted of 3 months of run-in or crossover followed by 9 months of maintenance. The primary endpoint was the number of blindly adjudicated nocturnal symptomatic hypoglycaemic episodes. Secondary endpoints included the occurrence of severe hypoglycaemia. We analysed all endpoints by intention-to-treat. RESULTS: Treatment with insulin degludec resulted in a 28% (95% CI: 9%-43%; P = .02) relative rate reduction (RRR) of nocturnal symptomatic hypoglycaemia at level 1 (≤3.9 mmol/L), a 37% (95% CI: 16%-53%; P = .002) RRR at level 2 (≤3.0 mmol/L), and a 35% (95% CI: 1%-58%; P = .04) RRR in all-day severe hypoglycaemia compared with insulin glargine U100. CONCLUSIONS: Patients with T1D prone to nocturnal severe hypoglycaemia have lower rates of nocturnal symptomatic hypoglycaemia and all-day severe hypoglycaemia with insulin degludec compared with insulin glargine U100.

Risk of Major Congenital Malformations or Perinatal or Neonatal Death With Insulin Detemir Versus Other Basal Insulins in Pregnant Women With Preexisting Diabetes: The Real-World EVOLVE Study.

OBJECTIVE: To compare the risk of severe adverse pregnancy complications in women with preexisting diabetes. RESEARCH DESIGN AND METHODS: Multinational, prospective cohort study to assess the prevalence of newborns free from major congenital malformations or perinatal or neonatal death (primary end point) following treatment with insulin detemir (detemir) versus other basal insulins. RESULTS: Of 1,457 women included, 727 received detemir and 730 received other basal insulins. The prevalence of newborns free from major congenital malformations or perinatal or neonatal death was similar between detemir (97.0%) and other basal insulins (95.5%) (crude risk difference 0.015 [95% CI -0.01, 0.04]; adjusted risk difference -0.003 [95% CI -0.03, 0.03]). The crude prevalence of one or more congenital malformations (major plus minor) was 9.4% vs. 12.6%, with a similar risk difference before (-0.032 [95% CI -0.064, 0.000]) and after (-0.036 [95% CI -0.081, 0.009]) adjustment for confounders. Crude data showed lower maternal HbA1c during the first trimester (6.5% vs. 6.7% [48 vs. 50 mmol/mol]; estimated mean difference -0.181 [95% CI -0.300, -0.062]) and the second trimester (6.1% vs. 6.3% [43 vs. 45 mmol/mol]; -0.139 [95% CI -0.232, -0.046]) and a lower prevalence of major hypoglycemia (6.0% vs. 9.0%; risk difference -0.030 [95% CI -0.058, -0.002]), preeclampsia (6.4% vs. 10.0%; -0.036 [95% CI -0.064, -0.007]), and stillbirth (0.4% vs. 1.8%; -0.013 [95% CI -0.024, -0.002]) with detemir compared with other basal insulins. However, differences were not significant postadjustment. CONCLUSIONS: Insulin detemir was associated with a similar risk to other basal insulins of major congenital malformations, perinatal or neonatal death, hypoglycemia, preeclampsia, and stillbirth.

Black paints covered with multidielectrics: light absorbers.

Black paints are commonly used to provide broadband light absorbers in high-precision optics. We show how multidielectric coatings improve the performances of these absorbers. The coated rough paints still exhibit a quasi-lambertian diffuse reflection, but this scattering pattern can be reduced by several orders of magnitude, which strongly enhances absorption. Predictions are based on an exact electromagnetic theory of light scattering from arbitrary rough multilayers. Results are also compared to useful approximate theories.

Sensitivity of resonance properties of all-dielectric multilayers driven by statistical fluctuations.

In photonics and emerging fields of quantum and topological materials, increasing demands are placed upon the state and control of electromagnetic fields. Dielectric multilayer materials may be designed and optimized to possess extremely sharp spectral and angular photonic resonances allowing for the creation of fields orders of magnitude larger than the exciting field. With enhancements of 104 and higher, the extreme nature of these resonances places high constraints on the statistical properties of the physical and optical characteristics of the materials. To what extent the spectral and angular shifts occur as a result of fluctuations in the refractive indices and morphologies of the involved low-loss subdomains have not been considered previously. Here, we present how parameter variations such as those caused by fluctuations in deposition rate, yielding bias, random and compensated errors, may affect the resonance properties of low-loss all-dielectric stacks.

Anti-scattering effect analyzed with an exact theory of light scattering from rough multilayers.

First-order theories of light scattering previously revealed the existence of anti-scattering effects in optical multilayers. Here we present an exact electromagnetic theory that is able to complete the scattering analysis when first-order scattering is cancelled. The theory is valid for arbitrary rough multilayers.

International round-robin experiment for angle-resolved light scattering measurement.

An international round-robin experiment has been conducted to test procedures and methods for the measurement of angle-resolved light scattering. ASTM E2387-05 has been used as the main guide, while the experience gained should also contribute to the new ISO standard of angle-resolved scattering currently under development (ISO/WD 19986:2016). Seven laboratories from Europe and the United States measured the angle-resolved scattering from Al/SiO2-coated substrates, transparent substrates, volume diffusors, quasi-volume diffusors, white calibration standards, and grating samples at laser wavelengths in the UV, VIS, and NIR spectra. Results were sent to Fraunhofer IOF, which coordinated the experiments and analyzed the data, while ESA-ESTEC, as the project donor, defined conditions and parameters. Depending mainly on the sample type, overall good to reasonable agreements were observed, with largest deviations at scattering angles very close to the specular beam. Volume diffusor characterization unexpectedly turned out to be challenging. Not all participants provided measurement uncertainty ranges according to the Guide to the Expression of Uncertainty in Measurement; often, a single general scatterometer-related measurement uncertainty value was stated. Although relative instrument measurement uncertainties close to 1% are sometimes claimed, the comparison results did not support these claims for specular scattering samples as mirrors, substrates, or gratings.

Bandwidths limitations of giant optical field enhancements in dielectric multi-layers.

Dielectric multilayers, when properly optimized, have been shown to sustain giant optical field enhancement directly linked to the imaginary index of the materials. Such giant optical field is of great interests to increase tremendously the sensitivity of optoelectronic systems. Unfortunately, this ultra-sensitive system is also highly depending on the illumination conditions. We discuss here the effect of the angular divergence and the spectral bandwidth of the incident laser beam on the absorption and field enhancement. In this study, we clearly show that giant optical field enhancements, up to several decades, may be achievable when the incident conditions are down few µrad and pm in term of angular and spectral bandwidths respectively.

Speckle intensity statistics for chromatic scattering media under partially polarized illumination.

Intensity contrast in a fully developed speckle pattern resulting from the elastic scattering of a partially polarized light from a strongly scattering medium is theoretically and numerically studied. Simple expressions are derived when the illumination bandwidth is much smaller or larger than the chromatic length of the scattering medium.

Thermal invisibility based on scattering cancellation and mantle cloaking.

We theoretically and numerically analyze thermal invisibility based on the concept of scattering cancellation and mantle cloaking. We show that a small object can be made completely invisible to heat diffusion waves, by tailoring the heat conductivity of the spherical shell enclosing the object. This means that the thermal scattering from the object is suppressed, and the heat flow outside the object and the cloak made of these spherical shells behaves as if the object is not present. Thermal invisibility may open new vistas in hiding hot spots in infrared thermography, military furtivity, and electronics heating reduction.

Analogies between optical propagation and heat diffusion: applications to microcavities, gratings and cloaks.

A new analogy between optical propagation and heat diffusion in heterogeneous anisotropic media has been proposed recently by three of the present authors. A detailed derivation of this unconventional correspondence is presented and developed. In time harmonic regime, all thermal parameters are related to optical ones in artificial metallic media, thus making possible to use numerical codes developed for optics. Then, the optical admittance formalism is extended to heat conduction in multilayered structures. The concepts of planar microcavities, diffraction gratings and planar transformation optics for heat conduction are addressed. Results and limitations of the analogy are emphasized.

Polarization analysis of speckle field below its transverse correlation width : application to surface and bulk scattering.

An experimental method for accurate polarimetric characterization of speckle field below its transverse correlation width is proposed. Using a polarimetric analyzer, the speckle field under investigation is probed by a set of polarimetric projections describing the full Poincaré sphere surface. Spatial polarimetric variations of the speckle field are thus observed with an accuracy of 1% for each Stokes parameter. Moreover, all the experimental data can be guaranteed by a validity criterion. Using white paper sheet and rough metal samples, the method exhibits strong potential to analyze and differentiate speckle fields generated by bulk and surface scattering.

Accurate metrology of polarization curves measured at the speckle size of visible light scattering.

An optical procedure is presented to measure at the speckle size and with high accuracy, the polarization degree of patterns scattered by disordered media. Whole mappings of polarization ratio, polarimetric phase and polarization degree are pointed out. Scattered clouds are emphasized on the Poincaré sphere, and are completed by probability density functions of the polarization degree. A special care is attributed to the accuracy of data. The set-up provides additional signatures of scattering media.