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[en] In this contribution, we report progress on the development of a hybrid lead/niobium superconducting RF (SRF) photoinjector. The goal of this effort is to build a Nb injector with the superconducting cathode made of lead, which demonstrated in the past superior quantum efficiency (QE) compared to Nb Three prototype hybrid devices, consisting of an all-niobium cavity with an arc-deposited spot of lead in the cathode region, have been constructed and tested. We present the cold test results of these cavities with and without lead.
[en] We report the experimental reconstruction of a nonclassicality quasiprobability for a single-photon-added thermal state. This quantity has significant negativities, which is necessary and sufficient for the nonclassicality of the quantum state. Our method exhibits several advantages compared to the reconstruction of the P function, since the nonclassicality filters used in this case can regularize the quasiprobabilities as well as their statistical uncertainties. A priori assumptions about the quantum state are therefore not necessary. We also demonstrate that, in principle, our method is not limited by small quantum efficiencies.
[en] We demonstrated a method for measuring the quantum efficiency of deep UV emission using the two-step excitation and the difference of the integrated spectral intensities in Pr3+-doped CaAl4O7 and SrAl4O7 crystals. The quantum efficiencies of the emission from the lowest 4f5d state in the two systems have been estimated to be less than 10% at room temperature. The effect of excited-state absorption of the lowest 4f5d state is analyzed for the quantum efficiency measurement. The actual efficiency may be higher when this effect is taken into account, especially under the condition of strong excitation
[en] Panchromatic organic photodetectors are demonstrated with a lead phthalocyanine (PbPc)/boron subphthalocyanine (SubPc) planar heterojunction, where PbPc and SubPc acted as the donor and non-fullerene acceptor, respectively. Primary absorption bands of PbPc locate in ultraviolet (UV) and near-infrared (NIR) regions, while it is visible region for SubPc. As a result, the optimized device shows a wide response covered the wavelengths from UV to NIR with an external quantum efficiency of 10.9% at about 590 nm, which is attributed to the simultaneous dissociation of the photogenerated excitons in both PbPc and SubPc. Besides, the device also exhibits a detectivity higher than 1010 Jones in the wavelength ranged from 350 to 950 nm. (paper)
[en] The transition of surface plasmon which was optically excited by attenuated total reflection(ATR)method is investigated by using photoacoustic method. We made a new suggestion that the dispersion relation of surface plasmon can be obtained by means of photoacustic technique. The radiative quantum efficiencies of surface plasmon are measured for three different wavelengths of incident light. (Author)
[en] The aim of this paper is a critical investigation of some correction factors in the quantum-efficiency calibration of photodetectors, in the photon-counting regime, by means of correlated photons generated through a parametric down-conversion process inside a non-linear crystal. An analysis is given of the main correction factors found in a real experimental situation, with different techniques for performing coincidence counts. (authors)
[en] New dedicated high quantum efficiency (Q.E.) photomultipliers (PMTs) have been produced by HAMAMATSU company, tested, selected and installed in the DAMA/LIBRA set-up at the Gran Sasso National Laboratory (LNGS) of the I.N.F.N.. In this paper the results obtained in the measurements of various features of these high Q.E. PMTs are reported, and some performances of DAMA/LIBRA in this new configuration are shown.
[en] Projective measurements with high quantum efficiency are often assumed to be required for efficient circuit-based quantum computing. We argue that this is not the case and show that the fact that they are not required was actually known previously but was not deeply explored. We examine this issue by giving an example of how to perform the quantum-ordering-finding algorithm efficiently using non-local weak measurements considering that the measurements used are of bounded weakness and some fixed but arbitrary probability of success less than unity is required. We also show that it is possible to perform the same computation with only local weak measurements, but this must necessarily introduce an exponential overhead.
[en] The efficiency of a radiation detector, intended as probability of detection of an incident quantum, depends on various factors: the detected fraction of quanta ascribed to the noise-less detector, the intrinsic noise of the detector, the false events introduced by the detection process and the false events generated by the detector itself. In this paper is treated the role of the false events on the measurement of the detective quantum efficiency (DQE) of the radiation detectors, indifferently for counting detectors and imaging detectors.
[en] Presented herein are the luminescence properties of several 1,4,5,8- polinahthalisoimides. The luminescence decay curves after deconvolution exhibit three decay times: τ1, τ2, and τ3.The luminescence lifetimes change along with the growth of excitation energy, as well as the contribution of each luminescence decay mechanism (A1, A2, and A3). The manner of change is distinct for one sample, namely, the pure E-isomer, in comparison to the others. The radiative deexcitation coupled with radiationless vibrational energy transfer to other luminescence centers, mainly other isomer units, is discussed as a possible deexcitation mechanism of fluorescence. The Kasha–Vavilov empirical rule is not fulfilled for the studied samples, as the luminescence quantum efficiency (ΦF) distinctly depends on the excitation wavelength (λexc). The quantum yield of one sample (about 63% of Z-isomer) is quite high, at 1%. - Highlights: • The fluorescence decay curves and quantum yields of naphthalimides are presented for the first time. • Luminescence decay curves (3 compounds) and deexcitation processes are discussed. • Fluorescence quantum efficiency measurements did not confirmed Kasha-Vavilov rule. • Large Stokes shift is regard as the main cause of the characteristics of the studied samples