Optical addressing of an individual erbium ion in silicon

The detection of electron spins associated with single defects in solids is a critical operation for a range of quantum information and measurement applications currently under development. To date, it has only been accomplished for two centres in crystalline solids: phosphorus in silicon using electrical readout based on a single electron transistor (SET) and nitrogen-vacancy centres in diamond using optical readout. A spin readout fidelity of about 90% has been demonstrated with both electrical readout and optical readout, however, the thermal limitations of the electrical readout and the poor photon collection efficiency of the optical readout hinder achieving the high fidelity required for quantum information applications. Here we demonstrate a hybrid approach using optical excitation to change the charge state of the defect centre in a silicon-based SET, conditional on its spin state, and then detecting this change electrically. The optical frequency addressing in high spectral resolution conquers the thermal broadening limitation of the previous electrical readout and charge sensing avoids the difficulties of efficient photon collection. This is done with erbium in silicon and has the potential to enable new architectures for quantum information processing devices and to dramatically increase the range of defect centres that can be exploited. Further, the efficient electrical detection of the optical excitation of single sites in silicon is a major step in developing an interconnect between silicon and optical based quantum computing technologies.Comment: Corrected the third affiliation. Corrected one cross-reference of "Fig. 3b" to "Fig. 3c". Corrected the caption of Fig. 3a by changing (+-)1 to

Medio ambiente acústico en el metro de Santiago

En este trabajo se analizan los niveles de ruido existentes en el metro de Santiago, tanto en banda ancha como en banda angosta. Se utilizan como cuantificadores L 1 0 , L5 0 , L 9 0, L 9 5, Leq y PSIL. Los valores encontrados en Leq, para un viaje típico en la línea 1, es de 86.2 dB (A) y en la linea 2 de 86.7 dB (A). Para L 5 0 se obtuvo un valor de 80.3 dB (A) para ambas líneas; el ruido de fondo que se puede asociar a L 9 5 es levemente superior a 70 dB (A). Los climas de ruido obtenidos para un viaje típico en línea 1 y 2 resulta ser 20 dB (A) y 20.5 dB (A), respectivamente. Los niveles encontrados para los distintos cuantificadores analizados, sobrepasan todos los límites recomendados

Interaction of chemical patterns in coupled layers

We investigate the interaction between reaction-diffusion systems coupled by diffusion. The photosensitive CDIMA (chorine dioxide–iodine–malonic acid) reaction allows us to study experimentally the mutual influence of two layers of Turing patterns coupled via a diffusive interaction. By illuminating each of the layers with different intensities of homogeneous external light, the chemical conditions in each layer can be shifted, allowing us to study the result of diffusive interaction between Turing patterns with different spatial configurations. Our experiments suggest a complex scenario for the interaction between different patterns, strongly dependent on the spatial characteristics of the interacting patterns. Numerical simulations are also reported in full agreement with experimental observationsThis work has been supported by the DGI (Spain) under Project No. FIS2010-21023 and Xunta de Galicia (Spain) under Project Nos. PGIDIT05PXIC20607PN and INCITE07PXI206131ES and by the NSF (USA). D.G.M. acknowledges a Ramon y Cajal Fellowship from the Ministry of Science and Technology of Spain and a Marie Curie International Reintegration Grant from the EU248346-NMSSBLS, as well as financial support from the CSIC-SPAIN (JAE-DOC

Limb reduction anomaly after failed misoprostol abortion

No Abstract

Isolation of alkaloids and anti-tumor activity of the crude methanolic extract of algerian Cytisus purgans

In this study, two known quinolizidine alkaloids which are sparteine and lupanine were isolated from the methanolic extract of the plant Cytisus purgans of Algerian flora by open column chromatography. These two compounds were identified on the basis of their spectral data (GC/MS, IR, MS, 1H and 13C). The anti-tumor activity of the crude methanolic extract of the aerial parts of the plant was also evaluated invitro against human breast cancer (MDA-MB-231) and human lung cancer (A549) cell lines using MTT assay

Suspended silicon integrated platform for the long-wavelength mid-infrared band

The atmospheric-transmission window and the fingerprint region of many substances overlaps with the long-wave infrared band. This has enabled the emergence of a new path for photonic integrated circuits, which could exploit the potential applications of this wavelength range, including chemical and bio sensing. In this work we review our latest advances in the suspended silicon platform with subwavelength grating lateral cladding at 7.7-µm wavelength. Suspended waveguides only require one lithographic etch step and can be specifically designed to maximize sensitivity when used as sensors. Waveguides with propagation loss of 3.1±0.3 dB/cm are demonstrated, as well as bends with less than 0.1 dB/bend. Suspended waveguides based on shifted Bragg grating lateral cladding are also reported, with propagation loss of 5.1±0.6 dB/cm. These results prepare the ground for the development of a platform capable of covering the entire mid-infrared band. Keywords: suspended silicon, mid-infrared, long-wave infrared, subwavelength grating, Bragg.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech