M. U. González

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Blood contains a range of protein biomarkers that could be used in the early detection of disease. To achieve this, however, requires sensors capable of detecting (with high reproducibility) biomarkers at concentrations one million times lower than the concentration of the other blood proteins. Here, we show that a sandwich assay that combines mechanical(More)
In this work we explore the first stages of quantum wire (QWR) formation studying the evolution of the growth front for InAs coverages below the critical thickness, theta(c), determined by reflection high energy electron diffraction (RHEED). Our results obtained by in situ measurement of the accumulated stress evolution during InAs growth on InP(001) show(More)
For a certain heteroepitaxial system, the optical properties of self-assembled nanostructures basically depend on their size. In this work, we have studied different ways to modify the height of InAs/ InP quantum wires QWrs in order to change the photoluminescence emission wavelength. One procedure consists of changing the QWr size by varying the amount of(More)
In this study, we report on ultrasensitive protein detection with lithographically prepared plasmonic nanostructures. We have engineered optical nanosensors by the combined approach of negative resist, electron beam lithography, and reactive ion etching to form highly reproducible arrays of gold dimers in which the near-field coupling in their subwavelength(More)
Aggregated metal nanoparticles exhibit enhanced localized electromagnetic fields that enable highly sensitive vibrational spectroscopy analysis based on surface-enhanced Raman scattering (SERS). We demonstrate SERS detection of organic analytes adsorbed to optically aggregated silver nanoparticles in a microfluidic device. The combination of optical(More)
Metal-dielectric Au-Co-SiO(2) magnetoplasmonic nanodisks are found to exhibit large magneto-optical activity and low optical losses. The internal architecture of the nanodisks is such that, in resonant conditions, the electromagnetic field undertakes a particular spatial distribution. This makes it possible to maximize the electromagnetic field at the(More)
The ability of gratings made of dielectric ridges placed on top of flat metal layers to open gaps in the dispersion relation of surface plasmon polaritons (SPPs) is studied, both experimentally and theoretically. The gap position can be approximately predicted by the same relation as for standard optical Bragg stacks. The properties of the gap as a function(More)
We report that the effect of an external magnetic field on the propagation of surface plasmons can be effectively modified through the coupling between localized (LSP) and propagating (SPP) surface plasmons. When these plasmon modes do not interact, the main effect of the magnetic field is a modification of the wavevector of the SPP mode, leaving the LSP(More)
In this work we discuss the excitation of parallel collective resonances in arrays of gold nanoparticles. Parallel collective resonances result from the coupling of the nanoparticles localized surface plasmons with diffraction orders traveling in the direction parallel to the polarization vector. While they provide field enhancement and delocalization as(More)
Surface plasmon waveguides (SPW’s) are metal ridges featuring widths in the micrometre range and thicknesses of a few tens of nanometres. A focused ion beam (FIB) has been used to carve micro–scatterers into gold SPW’s and the near–field distributions around these micro-structures are observed by means of a Photon Scanning Tunneling Microscope (PSTM). On(More)