We experimentally demonstrate a source of nearly pure single photons in arbitrary temporal shapes heralded from a parametric down-conversion (PDC) source at telecom wavelengths. The technology is ...enabled by the tailored dispersion of in-house fabricated waveguides with shaped pump pulses to directly generate the PDC photons in on-demand temporal shapes. We generate PDC photons in Hermite-Gauss and frequency-binned modes and confirm a minimum purity of 0.81, even for complex temporal shapes.
By projecting onto complex optical mode profiles, it is possible to estimate arbitrarily small separations between objects with quantum-limited precision, free of uncertainty arising from overlapping ...intensity profiles. Here we extend these techniques to the time-frequency domain using mode-selective sum-frequency generation with shaped ultrafast pulses. We experimentally resolve temporal and spectral separations between incoherent mixtures of single-photon level signals ten times smaller than their optical bandwidths with a tenfold improvement in precision over the intensity-only Cramér-Rao bound.
We report on the implementation of a time-multiplexed click detection scheme to probe quantum correlations between different spatial optical modes. We demonstrate that such measurement setups can ...uncover nonclassical correlations in multimode light fields even if the single mode reductions are purely classical. The nonclassical character of correlated photon pairs, generated by a parametric down-conversion, is immediately measurable employing the theory of click counting instead of low-intensity approximations with photoelectric detection models. The analysis is based on second- and higher-order moments, which are directly retrieved from the measured click statistics, for relatively high mean photon numbers. No data postprocessing is required to demonstrate the effects of interest with high significance, despite low efficiencies and experimental imperfections. Our approach shows that such novel detection schemes are a reliable and robust way to characterize quantum-correlated light fields for practical applications in quantum communications.
Any measurement scheme involving interference of quantum states of the electromagnetic field necessarily mixes information about the spatiotemporal structure of these fields and quantum states in the ...recorded data. We show that in this case, a trade-off is possible between extracting information about the quantum states and the structure of the underlying fields, with the modal overlap being either a goal or a convenient tool of the reconstruction. We show that varying quantum states in a controlled way allows one to infer temporal profiles of modes. Vice versa, for the known quantum state of the probe and controlled variable overlap, one can infer the quantum state of the signal. We demonstrate this trade-off by performing an experiment using the simplest on-off detection in an unbalanced weak homodyning scheme. For the single-mode case, we demonstrate experimentally inference of the overlap and a few-photon signal state. Moreover, we show theoretically that the same single-detector scheme is sufficient even for arbitrary multi-mode fields.
Deep inelastic (anti)neutrino–nucleus scattering Ansari, V.; Athar, M. Sajjad; Haider, H. ...
The European physical journal. ST, Special topics,
12/2021, Letnik:
230, Številka:
24
Journal Article
Recenzirano
Odprti dostop
The present status of the field theoretical model studies of the deep inelastic scattering induced by (anti)neutrino on the nuclear targets in a wide range of Bjorken variable
x
and four momentum ...transfer square
Q
2
has been reviewed (Haider et al. in Phys Rev C 84:054610, 2011, Phys Rev C 85:155201, 2012, Nucl Phys A 955:58, 2016; Zaidi et al. in Phys Rev D 99:093011, 2019, Phys Rev D 101:033001, 2020; Ansari et al. in Phys Rev D 102:113007, 2020). The effect of the nonperturbative corrections such as target mass corrections and dynamical higher twist effects, perturbative evolution of the parton densities, nuclear medium modifications in the nucleon structure functions, and nuclear isoscalarity corrections on the weak nuclear structure functions have been discussed. These structure functions have been used to obtain the differential scattering cross-sections. The various nuclear medium effects such as the Fermi motion, binding energy, nucleon correlations, mesonic contributions, shadowing and antishadowing corrections relevant in the different regions of
x
and
Q
2
have been discussed. The numerical results for the structure functions and the cross-sections are compared with some of the available experimental data including the recent results from MINERvA. The predictions are made in argon nuclear target which is planned to be used as a target material in DUNE at the Fermilab.
In the last few decades, there has been much progress on low loss waveguides, very efficient photon-number detectors and nonlinear processes. Engineered sum-frequency conversion is now at a stage ...where it allows operation on arbitrary temporal broadband modes, thus making the spectral degree of freedom accessible for information coding. Hereby the information is often encoded into the temporal modes of a single photon. Here, we analyse the prospect of using multi-photon states or squeezed states in different temporal modes based on integrated optics devices. We describe an analogy between mode-selective sum-frequency conversion and a network of spatial beam splitters. Furthermore, we analyse the limits on the achievable squeezing in waveguides with current technology and the loss limits in the conversion process.
This article is part of the themed issue ‘Quantum technology for the 21st century’.
Pure ZnO nanorods with various times, La-doped ZnO NRs and Dy-doped ZnO NRs were synthesized through two steps: seed layer by spin coating method and growing of nanorods by hydrothermal method. X-ray ...diffraction, field emission scanning electron microscopy, dispersive X-ray spectroscopy, photoluminescence spectroscopy and ultraviolet–visible spectrometer were used to investigate the structure composition and the optical properties of the products. The optical measurements indicated an enhancement in absorption and emission intensity, when the length of nanorods and impurities concentration were increased and furthermore, the band gap of ZnO nanorods was decreased. Dye-Sensitized Solar Cells were fabricated using ZnO nanorods grown on the porous TiO2 nanoparticles film (TiO2 NPs/ZnO NRs) as the photoanodes. The effect of different growth time and various dopants were investigated on the performance of DSSCs. The optimum performance of DSSC was achieved by ZnO NRs grown for 300 min. The performance of DSSC based TiO2 NPs/ZnO NRs decorated with TiO2 NPs was obtained 5.99% and cell efficiency was improved more than twice compared with the undecorated photoanode. The power conversion efficiency of DSSCs doped with Lanthanum and Dysprosium was also increased by 63.6% and 71.5%, respectively, in comparison with the conventional TiO2 NPs photoanode.
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•Pure, La-doped and Dy-doped ZnO nanorods were grown by a simple hydrothermal method and characterized.•DSSCs were fabricated using pure, La-doped and Dy-doped ZnO nanorods.•The efficiency of DSSCs doped with La and Dy was increased by 63.6 % and 71.5 %, respectively, in comparison with the conventional TiO2 NPs photoanode.
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