10 research outputs found

    Adding Spin Functionality to Traditional Optoelectronics via Chiral Perovskite

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    Spin polarized current generation and injection into semiconductors at room temperature are key to enable a broader range of opto-spintronic functionalities, yet the inherent efficiency of spin injection across commonly used semiconductor-ferromagnet interfaces is limited. Here, we demonstrate efficient spin injection into commercially viable III-V light emitting diodes (LED) by integrating chiral halide perovskite layers with (AlxGa1-x)0.5In0.5P multiple quantum wells (MQW). Spin polarized current is injected via chirality induced spin selectivity (CISS) and the spin accumulation in the III-V semiconductor is detected via the emission of circularly polarized light with a degree of circular polarization of up to ~ 15%. X-ray photoemission spectroscopy (XPS) and transmission electron microscopy (TEM) cross sectional imaging indicate a pristine perovskite/III-V interface. These findings demonstrate chiral perovskite semiconductors transform well-developed semiconductor platforms to enable control over spin, charge, and light

    Photonic quasi-crystal terahertz lasers

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    Quasi-crystal structures do not present a full spatial periodicity but are nevertheless constructed starting from deterministic generation rules. When made of different dielectric materials, they often possess fascinating optical properties, which lie between those of periodic photonic crystals and those of a random arrangement of scatterers. Indeed, they can support extended band-like states with pseudogaps in the energy spectrum, but lacking translational invariance, they also intrinsically feature a pattern of ‘defects’, which can give rise to critically localized modes confined in space, similar to Anderson modes in random structures. If used as laser resonators, photonic quasi-crystals open up design possibilities that are simply not possible in a conventional periodic photonic crystal. In this letter, we exploit the concept of a 2D photonic quasi crystal in an electrically injected laser; specifically, we pattern the top surface of a terahertz quantum-cascade laser with a Penrose tiling of pentagonal rotational symmetry, reaching 0.1–0.2% wall-plug efficiencies and 65 mW peak output powers with characteristic surface-emitting conical beam profiles, result of the rich quasi-crystal Fourier spectrum

    Are the measurement properties of incremental exercise tests similar between patients with COPD and CHF?

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    We investigated whether the differences in exercise limitation between patients with chronic obstructive pulmonary disease (COPD) or chronic heart failure (CHF) affect the repeatability or responsiveness of incremental exercise tests. Patients with COPD (Medical Research Council dyspnoea grade 2–5) and patients with CHF (New York Heart Association class II–IV) performed two incremental shuttle walk tests (ISWT) following familiarisation and two incremental cycle ergometer tests (ICE) within 2 weeks. Both tests were repeated on completion of a pulmonary rehabilitation (PR) programme. One hundred and twelve patients were recruited. In response to exercise, patients with COPD were more likely than patients with CHF to have a ventilatory limitation (p 0.20 for all comparisons). The coefficient of repeatability across the cohort was 60 m for the ISWT and 0.270 L/minute for ICE VO2Peak. The minimum important difference (MID) for the ISWT in both diseases for PR was 30 m. The repeatability and responsiveness of the ISWT distance and ICE VO2Peak are similar between patients with COPD and CHF and are unaffected by differences in exercise limitation. A change of 60 m in the ISWT or 0.270 L/minute in ICE VO2Peak is required to be 95% certain that a true change has occurred within an individual patient. For a group of patients with either COPD or CHF, the MID for the ISWT distance is estimated to be 30 m

    Association of the PHACTR1/EDN1 Genetic Locus With Spontaneous Coronary Artery Dissection

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    Cohort profile. the ESC-EORP chronic ischemic cardiovascular disease long-term (CICD LT) registry

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    The European Society of cardiology (ESC) EURObservational Research Programme (EORP) Chronic Ischemic Cardiovascular Disease registry Long Term (CICD) aims to study the clinical profile, treatment modalities and outcomes of patients diagnosed with CICD in a contemporary environment in order to assess whether these patients at high cardiovascular risk are treated according to ESC guidelines on prevention or on stable coronary disease and to determine mid and long term outcomes and their determinants in this population
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