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We put forward the concept of quantum spiral bandwidth of the spatial mode function of the two-photon entangled state in spontaneous parametric downconversion. We obtain the bandwidth using the eigenstates of the orbital angular momentum of…

Quantum Physics · Physics 2009-11-10 J. P. Torres , A. Alexandrescu , L. Torner

We present an experimental and theoretical study of photon pairs generated by spontaneous four wave mixing (SFWM), based on birefringent phasematching, in a fiber which supports more than one transverse mode. We present SFWM spectra,…

Correlations between photons are interesting for a number of applications and concepts in metrology in particular for resolution improvements in different methods of quantum imaging. Since Fock-states of N-photons of wavelength lambda in…

Quantum Physics · Physics 2015-05-13 Martin Ostermeyer , Dirk Puhlmann , Dietmar Korn

We report an experiment in which the moments of spatial coordinates of down-converted photons are measured directly, without having to reconstruct any marginal probability distributions. We use a spatial light modulator to couple the…

Quantum Physics · Physics 2015-06-18 M. Hor-Meyll , J. O. de Almeida , G. B. Lemos , P. H. Souto Ribeiro , S. P. Walborn

Photon pair entangled in high dimensional orbital angular momentum (OAM) degree of freedom (DOF) has been widely regarded as a possible source in improving the capacity of quantum information processing. The need for the generation of a…

Quantum Physics · Physics 2020-05-20 Shilong Liu , Yingwen Zhang , Chen Yang , Shikai Liu , Zheng Ge , Yinhai Li , Yan Li , Zhiyuan Zhou , Guangcan Guo , Baosen Shi

In this work, we demonstrate optical integration using heralded single photons and explore the influence of spatial correlations between photons on this process. Specifically, we experimentally harness the transverse spatial degrees of…

Quantum entanglement, the non-separability of a multipartite wave function, became essential in understanding the non-locality of quantum mechanics. In optics, this non-locality can be demonstrated on impressively large length scales, as…

Metasurfaces are highly effective at manipulating classical light in the linear regime; however, effectively controlling the polarization of non-classical light generated from nonlinear resonant metasurfaces remains a challenge. Here, we…

Biphoton process is an essential benchmark for quantum information science and technologies, while great efforts have been made to improve the coherence of the system for better quantum correlations. Nevertheless, we find that the…

Quantum Physics · Physics 2023-12-01 Kangkang Li , Yin Cai , Jin Yan , Zhou Feng , Fu Liu , Lei Zhang , Feng Li , Yanpeng Zhang

Structured optical materials provide a promising platform for photonic quantum information processing in free space. Beam splitters, a fundamental building block of photonic circuits, have recently been demonstrated in free space using…

Correlated photons produced by spontaneous parametric down-conversion are an essential tool for quantum communication, especially suited for long-distance connections. To have a reasonable count rate after all the losses in the propagation…

Quantum Physics · Physics 2009-11-10 Valerio Scarani , Hugues de Riedmatten , Ivan Marcikic , Hugo Zbinden , Nicolas Gisin

Polarization of photons plays a key role in quantum optics and light-matter interactions, however, it is difficult to control in nanosystems since the eigenstate of a nanophotonic cavity is usually fixed and linearly polarized. Here we…

The role of multi-parameter entanglement in quantum interference from collinear type-II spontaneous parametric down-conversion is explored using a variety of aperture shapes and sizes, in regimes of both ultrafast and continuous-wave…

The conditions required for spontaneous parametric down-conversion in a waveguide with periodic nonlinearity in the presence of an unguided pump field are established. Control of the periodic nonlinearity and the physical properties of the…

We explore the effects of ultrafast shaped pulses for two-level systems that do not have a single photon resonance by developing a multiphoton density-matrix approach. We take advantage of the fact that the dynamics of the intermediate…

Optics · Physics 2009-11-07 S. Abbas Hosseini , Debabrata Goswami

Properties of weak spatio-spectral twin beams in paraxial approximation are analyzed using the decomposition into appropriate paired modes. Numbers of paired modes as well as numbers of modes in the signal (or idler) field in the transverse…

Quantum Physics · Physics 2016-01-05 Jan Perina

The realization of efficient and miniature source of entangled photon pairs stills remains a challenge. In this work, we experimentally studied the possibility to enhance the process of spontaneous parametric down-conversion by surface…

Optics · Physics 2018-08-01 Ardi Loot , Ilmo Sildos , Valter Kiisk , Tavo Romann , Vladimir Hizhnyakov

Multiphoton correlations in linear photonic quantum networks are governed by matrix permanents. Yet, surprisingly few systematic properties of these crucial algebraic objects are known, while their calculation is a computationally hard…

Quantum Physics · Physics 2025-01-10 Tom A. W. Wolterink , Matthias Heinrich , Stefan Scheel , Alexander Szameit

We present an experimental study of the non-classical correlations of a pair of spatial qubits formed by passing two down-converted photons through a pair of double slits. After confirming the entanglement generated in our setup by quantum…

We study two-photon excitation using biphotons generated via the process of spontaneous parametric down-conversion in a nonlinear crystal. We show that the focusing of these biphotons yields an excitation distribution that is essentially…