A set of biochemical and histological responses was measured in wild gudgeon collected upstream and downstream of urban and pharmaceutical manufacture effluents. These individual end-points were associated to fish assemblage characterisation. Responses of biotransformation enzymes, neurotoxicity and endocrine disruption biomarkers revealed contamination of investigated stream by a mixture of pollutants. Fish from sampled sites downstream of the industrial effluent exhibited also strong signs of endocrine disruption including vitellogenin induction, intersex and male-biased sex-ratio. These individual effects were associated to a decrease of density and a lack of sensitive fish species. This evidence supports the hypothesis that pharmaceutical compounds discharged in stream are involved in recorded endocrine disruption effects and fish population disturbances and threaten disappearance of resident fish species. Overall, this study gives argument for the utilisation of an effect-based monitoring approach to assess impacts of pharmaceutical manufacture discharges on wild fish populations.
Realizing single photon sources emitting in the telecom band on silicon substrates is essential to reach complementary-metal-oxide-semiconductor (CMOS) compatible devices that secure communications over long distances. In this work, we propose the monolithic growth of needlelike tapered InAs/InP quantum dot-nanowires (QD-NWs) on silicon substrates with a small taper angle and a nanowire diameter tailored to support a single mode waveguide. Such a NW geometry is obtained by a controlled balance over axial and radial growths during the gold-catalyzed growth of the NWs by molecular beam epitaxy. This allows us to investigate the impact of the taper angle on the emission properties of a single InAs/InP QD-NW. At room temperature, a Gaussian farfield emission profile in the telecom O-band with a beam divergence angle θ = 30° is demonstrated from a single InAs QD embedded in a 2° tapered InP NW. Moreover, single photon emission is observed at cryogenic temperature for an off-resonant excitation and the best result, g 2 (0) = 0.05, is obtained for a 7° tapered NW. This all-encompassing study paves the way for the monolithic integration on silicon of an efficient single photon source in the telecom band based on InAs/InP QD-NWs.Epitaxy, Gaussian far-field emission profile, Telecom band, Silicon integration Non-classical light sources emitting at optical communication wavelength bands are of prime importance to quantum communication applications. One of these sources is the single photon source (SPS) which is the building block for realizing scalable on-chip devices for quantum 3 information processing. Once the single photons are generated, it is then required to manipulate the photons either to encode the information or to make the measurements. This means that the SPS must be integrated with compact photonic devices that can combine many optical components. Thanks to its large refractive index, silicon (Si) facilitates the fitting of a high number of optical components into a small device size making it a powerful platform for photonic integrated circuits. 1 Moreover, Si appears to be the most compatible material, due to the maturity of the complementary-metal-oxide-semiconductor (CMOS) fabrication methods, to combine electronics with photonics. 2 However, Si is an indirect band gap material which makes it a very poor light source. This issue can be solved by the monolithic integration, bonding or pick-andplace procedure of III-V materials on Si to fabricate CMOS compatible SPS. [3][4][5][6] In addition to the substrate choice, SPS emitting in the 1.3 µm and 1.5 µm telecom windows are required to reduce the losses for fiber-based long-haul communications. In particular, InAs quantum dots (QDs) have proven to be good candidates as efficient non classical light sources in these bands. 7,8 This requires embedding the QD in a nanophotonic structure such as nanowires (NWs), 9 micropillars, 10 optical horns, 11 photonic crystal cavities 12,13 and waveguides 14 in order to guide and efficiently extract the light in free space...
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