High-speed stimulated Brillouin scattering spectroscopy at 780 nm

We demonstrate a high-speed stimulated Brillouin scattering (SBS) spectroscopy system that is able to acquire stimulated Brillouin gain point-spectra in water samples and Intralipid tissue phantoms over 2 GHz within 10 ms and 100 ms, respectively, showing a 10-100 fold increase in acquisition rates over current frequency-domain SBS spectrometers. This improvement was accomplished by integrating an ultra-narrowband hot rubidium-85 vapor notch filter in a simplified frequency-domain SBS spectrometer comprising nearly counter-propagating continuous-wave pump-probe light at 780 nm and conventional single-modulation lock-in detection. The optical notch filter significantly suppressed stray pump light, enabling detection of stimulated Brillouin gain spectra with substantially improved acquisition times at adequate signal-to-noise ratios (∼25 dB in water samples and ∼15 dB in tissue phantoms). These results represent an important step towards the use of SBS spectroscopy for high-speed measurements of Brillouin gain resonances in scattering and non-scattering samples

Three-dimensional Localization of Fluorescent Emitters at the Nano-scale

We demonstrate nanometer-level localization accuracy of a single fluorescent emitter in three dimensions. Our super resolution microscopy technique is based on spectral self-interference for axial localization and two-dimensional diffraction pattern analysis for lateral localization

Three-dimensional nano-localization of single fluorescent emitters

We present a combination of self-interference microscopy with lateral super-resolution microscopy and introduce a novel approach for localizing a single nano-emitter to within a few nanometers in all three dimensions over a large axial range. We demonstrate nanometer displacements of quantum dots placed on top of polymer bilayers that undergo swelling when changing from an air to a water environment, achieving standard deviations below 10 nm for axial and lateral localization

Pesticides in the real world: The consequences of GMO-based intensive agriculture on native amphibians.

Pesticide use has been suggested as one of the major drivers of the global amphibian decline. Laboratory andmesocosm studies have addressed several questions to understand the mechanism by which pesticides causedetrimental effects on amphibians. However, the extrapolation of those results to natural populations may not beadequate to predict environmental impacts or to understand the role of pesticides in the amphibian decline. Byusing in situ enclosures, we evaluated the effects (survival and mobility) of common pesticides applied byfarmers (cypermethrin, chlorpyrifos, endosulfan, glyphosate, and 2,4-Dichlorophenoxyacetic acid) on tadpoles.We assessed these effects in four common amphibian species from South America across 91 ponds located in thePampas of central Argentina. We found that survival decreased in 13 out of 20 pesticides applications concomitantlywith detection of pesticides in water ponds. 48 h after applications, mixtures containing endosulfanor chlorpyrifos reduced tadpole survival to<1% while the cypermethrin mixtures reduced survival to 10%. Inaddition, we found impairment of mobility in all combination of pesticides, including glyphosate. The ecologicalcontext involved in our study represents the common exposure scenarios related to GMO-based agriculturepractices in South America, with relevance at regional levels. We emphasize that multifaceted approaches developedto understand the role of pesticides in the amphibian decline need a conservation perspective. This willbe achieved by work focusing on the integrated use of state-of-the-art techniques and resources for documentingpesticide effects over wild amphibians´ populations, allowing conservation scientists to generate better managementrecommendations.Fil: Agostini, Maria Gabriela. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Ecología, Genética y Evolución de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Ecología, Genética y Evolución de Buenos Aires; ArgentinaFil: Roesler, Carlos Ignacio. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Ecología, Genética y Evolución de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Ecología, Genética y Evolución de Buenos Aires; ArgentinaFil: Bonetto, Carlos Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Limnología "Dr. Raúl A. Ringuelet". Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Instituto de Limnología; ArgentinaFil: Ronco, Alicia Estela. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Departamento de Química. Centro de Investigaciones del Medio Ambiente; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; ArgentinaFil: Bilenca, David Norberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Ecología, Genética y Evolución de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Ecología, Genética y Evolución de Buenos Aires; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Biodiversidad y Biología Experimental; Argentin

Differential near-field scanning optical microscopy using sensor arrays

In this paper, we introduce a new aperture-type near-field scanning optical microscopy (NSOM) imaging concept that relies on specially designed large-area (e.g., &gt;200 nm x 200 nm) aperture geometries having sharp corners. Unlike in conventional NSOM, the spatial resolution of this near-field imaging modality is not determined by the size of the aperture, but rather by the sharpness of the corners of the large aperture. This approach significantly improves the light throughput of the near-field probe and, hence, increases the SNR. Here, we discuss the basic concepts of this near-field microscopy approach and illustrate both theoretically and experimentally how an array of detectors can be utilized to further improve the SNR of the near-field image. The results of this work are particularly relevant for imaging of biological samples at a spatial resolution of quality