Third-order optical autocorrelator for time-domain operation at telecommunication wavelengths

We report on amorphous organic thin films that exhibit efficient third-harmonic generation at telecommunication wavelengths. At 1550 nm, micrometer-thick samples generate up to 17 µW of green light with input power of 250 mW delivered by an optical parametric oscillator. This high conversion efficiency is achieved without phase matching or cascading of quadratic nonlinear effects. With these films, we demonstrate a low-cost, sensitive third-order autocorrelator that can be used in the time-frequency domain

Ultrafast-pulse diagnostic using third-order frequency-resolved optical gating in organic films

We report on the diagnostic of ultrafast pulses by frequency-resolved optical gating (FROG) based on strong third-harmonic generation (THG) in amorphous organic thin films. The high THG conversion efficiency of these films allows for the characterization of sub-nanojoule short pulses emitting at telecommunication wavelengths using a low cost portable fiber spectrometer

Spectral distortions from promising single and multifield inflationary models

Forthcoming missions probing the absolute intensity of the CMB are expected to be able to measure spectral distortions, which are deviations from its blackbody distribution. As cosmic inflation can induce spectral distortions, these experiments offer a possibility to further test the various promising inflationary proposals, whose predictions need to be carefully determined. After numerically fitting all inflationary observables to match current observations, we compute the predicted spectral distortions of various promising single and multifield inflationary models. The predictions of single-field inflationary models display deviations between 1% and 20% with respect to the standard cosmological model in the observable window, where multi-natural and axion-monodromy inflation stand out in this respect. In the case of multifield inflation, we observe a richer structure of the power spectrum, which, in the case of so-called hybrid attractors, yields spectral distortions about 100 times more intense than the standard signal. These observations open up questions about the relation among our results and other cosmological observables that are also to be probed soon.Comment: 30 pages + references, 17 figures, 6 table

Third-order nonlinear optical response and photoluminescence characterization of tellurite glasses with different alkali metal oxides as network modifiers

Studies of the third-order nonlinear optical properties in TeO(2)-MO-R(2)O glasses with three different alkali metal oxides R(2)O (R - Li, Na, K) as network modifiers and two network intermediates MO (M - Zn, Mg) are reported. The influence of such modifiers and intermediates on the nonlinear optical properties of these glasses was investigated using the standard Z-scan and the thermally managed Z-scan techniques under femtosecond pulse excitation at 800 nm. For different modifiers and intermediates, the nonlinear refraction indices n(2) of these glasses varied in the range 1.31-2.81 (x10(-15) cm(2)/W). It was found that n(2) increases as the ionic radius of both network modifiers and intermediates decreases. Furthermore, the measurements show that the contribution from thermo-optical effects to the nonlinear refraction index is negligible for all of the studied glass compositions. In addition, the effect of modifiers and intermediates in the formation of localized states in the vicinity of the optical bandgap was also studied through photoluminescence experiments. These experiments revealed the presence of two emission bands (red and blue) originating from these localized states that can be populated after optical excitation and subsequent relaxation

Changes in the membrane proteome of human chronic kidney diseased erythrocytes

Comunicaciones a congreso

Effect of Diacerein on Insulin Secretion and Metabolic Control in Drug-Naïve Patients With Type 2 Diabetes: A randomized clinical trial

OBJECTIVE - To assess the effect of diacerein on insulin secretion and metabolic control in drug-naïve patients with type 2 diabetes. RESEARCH DESIGN AND METHODS - A randomized, double-blind, placebo-controlled clinical trial was carried out in 40 drug-naïve adult patients with type 2 diabetes. A metabolic profile including interleukin (IL)-1β, tumor necrosis factor-a, IL-6, and fasting insulin levelswas carried out before the intervention and 2months afterward. A hyperglycemic-hyperinsulinemic clamp technique was performed to assess the phases of insulin secretion and insulin sensitivity. After randomization, 20 patients received diacerein (50mg once daily) for the first 15 days and twice daily for 45 additional days. The remaining patients received placebo. Intra- and intergroup differences were calculated by Wilcoxon signed rank and Mann-Whitney U tests. RESULTS-Therewere significant increases in first (102 ± 63 vs. 130 ± 75 pmol/L; P<0.01), late (219 ± 111 vs. 280 ± 135 pmol/L; P<0.01), and total insulin (178691 vs. 216699pmol/L; P<0.01) secretionswithout changes in insulin sensitivity after diacerein administration. There were significant decreases in fasting glucose (7.9 ± 1.4 vs. 6.8 ± 1.0mmol/L; P<0.01) and in A1C levels (8.3 ± 1.0 vs. 7.0 ± 0.8%; P < 0.001) after diacerein administration. There were no significant changes after placebo administration in the above-mentioned evaluations. CONCLUSIONS - Insulin secretion increased and metabolic control improved after diacerein administration in drug-naïve patients with type 2 diabetes. © 2011 by the American Diabetes Association

Acoustically Levitated Whispering-Gallery Mode Microlasers

Acoustic levitation has become a crucial technique for contactless manipulation in several fields, particularly in biological applications. However, its application in the photonics field remains largely unexplored. In this study, we implement an affordable and innovative phased-array levitator that enables stable trapping in the air of micrometer dye-doped droplets, thereby enabling the creation of microlasers. For the first time, this paper presents a detailed performance of the levitated microlaser cavity, supported by theoretical analysis concerning the hybrid technology based on the combination of whispering-gallery modes and acoustic fields. The pressure field distribution inside the acoustic cavity is numerically solved and qualitatively matched with the schlieren deflectometry technique. The optical lasing features of the levitated microlasers are highly comparable with those devices based On-a-Chip registering maximum Q-factors of ~ 105, and minimum lasing thresholds ~ 150 nJ cm−2. The emission comb is explained as a sum of multiple individual-supported whispering-gallery modes. The use of novel touchless micrometric lasers, produced with an acoustic levitator brings new technological opportunities based on photonic-acoustic technological platforms