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In order to study the potential applications of quantum correlation measurement and Hong-Ou-Mandel (HOM) interference to laser detection and ranging (LADAR) systems, the method for preparing the correlated two-photon source based on dispersion-shifted fiber (DSF) and the HOM interference principle of identical photons was adopted. A correlated two-photon generation platform and a HOM interferometer for weak coherent light interference experiment were assembled for theoretical analysis and experimental verification. The results show that, the correlated two-photon source has the maximum two-photon generation rate and the ratio of coincidence to accidental coincidence count of about 8kHz and 15, respectively. The visibility of HOM interference fringe is 0.41 ± 0.01, HOM interference can improve the time measuring precision of LADAR to 0.95ps ± 0.03ps, corresponding to a spatial resolution of 284.06µm ±9.94µm. The results lay a foundation for further research to improve LADAR performance by using quantum optics technologies. [ABSTRACT FROM AUTHOR]

Photodetectors based on InGaAs nanowires have been widely studied due to their excellent properties. The detection mechanism, material structure, device performance and current research status of InGaAs nanowire photodetectors were reviewed. The key technologies, such as the structure design of InGaAs nanowire avalanche focal plane detector, the precise growth of nanowire materials, the interface and defect control of nanowire materials, and the preparation process of nanowire avalanche focal plane devices were discussed. On this basis, the prospect of developing high photon detection efficiency, low noise and high gain InGaAs nanowire avalanche focal plane detector was prospected. [ABSTRACT FROM AUTHOR]

Two-dimensional (2D) materials and their corresponding van der Waals (vdW) heterostructures are considered as promising candidates for highly efficient solar cell applications. A series of 2D HfX2 (X = Cl, Br, I) monolayers are proposed, via first-principle calculations. The vibrational phonon spectra and molecular dynamics simulation results indicate that HfX2 monolayers possess dynamical and thermodynamical stability. Moreover, their electronic structure shows that their Heyd–Scuseria–Ernzerhof(HSE06)-based band values (1.033–1.475 eV) are suitable as donor systems for excitonic solar cells (XSCs). The material's significant visible-light absorbing capability (∼105 cm−1) and superior power conversion efficiency (∼20%) are demonstrated by establishing a reasonable type II vdW heterostructure. This suggests the significant potential of HfX2 monolayers as a candidate material for XSCs. [ABSTRACT FROM AUTHOR]

Quantum emitters serve as the building blocks of quantum network, connecting quantum computing, quantum communication and quantum metrology. Semiconductor quantum dots ( QDs) are widely considered as the best candidate for quantum emitters. By a decade of effort, the controllability, purity, brightness, indistinguishability, and coherence of QD emitters are greatly improved so that they are much closer to the application level. In this paper, the scientific and technological development of quantum emitters based on QDs were reviewed. Firstly, QD-based single photon sources have achieved indistinguishability of near unity, high purity, and high extraction efficiency. Secondly, QD-based entangled photon emitters have achieved high bit rate, high entanglement fidelity by improvements such as eliminating fine structure splitting. Thirdly, remarkable development has been made towards on-chip integration of QD emitters into planar circuits and nano-photonic systems. It turns out that quantum emitters based on semiconductor QDs are greatly potential to be applied in quantum information processing systems in the near future. [ABSTRACT FROM AUTHOR]