Preparing arbitrary pure states of spatial qudits with a single phase-only spatial light modulator

We present a new method for preparing multidimensional spatial qudits by means of a single phase-only spatial light modulator (SLM). This method improves previous ones that use two SLMs, one working in amplitude regime and the other in phase regime. To that end, we addressed diffraction gratings on the slits that define the state and then we performed a spatial filtering in the Fourier plane. The amplitude of the coefficients of the quantum state are determined by the modulation deep of the diffraction gratings, and the relative phase is the mean phase value of the diffraction gratings. This encoding result to be more compact, less expensive and use the photons more efficiently.Instituto de Física La Plat

Preparing arbitrary pure states of spatial qudits with a single phase-only spatial light modulator

We present a new method for preparing multidimensional spatial qudits by means of a single phase-only spatial light modulator (SLM). This method improves previous ones that use two SLMs, one working in amplitude regime and the other in phase regime. To that end, we addressed diffraction gratings on the slits that define the state and then we performed a spatial filtering in the Fourier plane. The amplitude of the coefficients of the quantum state are determined by the modulation deep of the diffraction gratings, and the relative phase is the mean phase value of the diffraction gratings. This encoding result to be more compact, less expensive and use the photons more efficiently.Instituto de Física La Plat

Preparing arbitrary pure states of spatial qudits with a single phase-only spatial light modulator

We present a new method for preparing multidimensional spatial qudits by means of a single phase-only spatial light modulator (SLM). This method improves previous ones that use two SLMs, one working in amplitude regime and the other in phase regime. To that end, we addressed diffraction gratings on the slits that define the state and then we performed a spatial filtering in the Fourier plane. The amplitude of the coefficients of the quantum state are determined by the modulation deep of the diffraction gratings, and the relative phase is the mean phase value of the diffraction gratings. This encoding result to be more compact, less expensive and use the photons more efficiently.Instituto de Física La Plat

Characterizing the Backscattered Spectrum of Mie Spheres

The data that support the findings of this study are available from the corresponding author upon reasonable request. The data used for the figures and results in this article can be found at the digital.csic.es repository http://hdl.handle.net/10261/339860This study describes both experimentally and theoretically an important hitherto undiscovered feature of the scattering of micron-sized spherical objects when illuminated with highly focused circularly polarized light. This is a regime of high experimental relevance which has not been described in full detail. The experiments are complemented with the analytical formulas explaining the field scattered directed toward the backward hemispace. In particular, it is proven that this field shows a very regular oscillatory dependency with the optical size. This phenomenon is typically hidden in the total scattered field, as the field is scattered much less toward the backward hemisphere than toward the forward one. These regular oscillations are measured experimentally. It is proven that, by analyzing them, it is possible to determine the index of refraction of isolated micron-sized particles, opening new paths for applications in sensing and metrology.M.M.F acknowledges financial support from MCIN/AEI/10.13039/501100011033 and “ESF Investing in your Future” through Project Ref. No PRE2018-085136. M.M.F. and G.M.T. acknowledge financial support from MCIN/AEI/10.13039/501100011033 through Project Ref. No. FIS2017-87363-P. Á.N. acknowledges financial support from MCIN/AEI/10.13039/501100011033 and “ESF Investing in your Future” through Project Ref. No. BES-2017-080073. Á.N., R.E., and J.A. acknowledge financial support from MCIN/AEI/10.13039/501100011033 and “ERDF A way of making Europe” through Project Ref. No. PID2022-139579NB-L00. M.M.F., Á.N., J.J.M.V., R.E., J.A. and G.M.T. acknowledgefinancial suport from the Department of Education, Research and Universities of the Basque Government through Project Ref. No. IT 1526-22. M.M.F., J.L.A., I.G.V., J.J.M.V. and G.M.T. acknowledge financial support from CSIC Research Platform PTI-001. M.B.B. acknowledges financial support from MCIN/AEI/10.13039/501100011033 through Project Ref. No. MDM-2016-0618. J.O.T. acknowledges financial support from MCIN/AEI/10.13039/501100011033 and the European Union NextGenerationEU/PRTR through the Juan de la Cierva Fellowship Ref. No. FJC2021-047090-I, and from MCIN/AEI/10.13039/501100011033 and “ERDF A way of making Europe” through Project Ref. No. PID-2022-137569NBC43. C.L. acknowledges financial support from MCIN/AEI/10.13039/501100011033 through Project Ref. No. PID2021-124814NB-C21.The data used for the figures and results in this article can be found at the digital.csic.es repository http://hdl.handle.net/10261/339860Peer reviewe

Implementation and characterization of quantum channels on ddimensional spatial systems

Resumen del trabajo presentado a la Spanish Conference on Nanophotonics (Conferencia Española de Nanofotónica-CEN), celebrada en Donostia-San Sebastián (España) del 3 al 5 de octubre de 2018.We propose a simple optical architecture, based on phase-only programmable spatial light modulators, in order to characterize general processes on photonic spatial quantum systems in a d > 2 Hilbert space. We demonstrate the full reconstruction of typical noises affecting quantum computing, as amplitude shifts, phase shifts, and depolarizing channel in dimension d = 5. We have also reconstructed simulated atmospheric turbulences affecting a free-space transmission of qudits in dimension d = 4. In each case, quantum process tomography (QPT) was performed in order to obtain the matrix χ that fully describe the corresponding quantum channel, E. Fidelities between the states experimentally obtained after go through the channel and the expected ones are above 97%. For example, in the figure above we show an amplitude-shift (AS) process: Real part of the process matrices χ in d=5. Plots (a) and (b) correspond to the ideal process matrices, in the basis defined by tensor products of the projectors Pij (i,j=0, 1,...,d-1), for an uniform AS and an uniform respect to 0 AS, respectively. The imaginary parts are identically zero. Plots (c) and (d) are the corresponding experimental matrices obtained after SQPT.Peer reviewe

Bandwidth control of the biphoton wavefunction exploiting spatio-temporal correlations

This article is dedicated to the memory of Juan José Sáenz.In this work we study the spatio-temporal correlations of photons produced by spontaneous parametric down conversion. In particular, we study how the waists of the detection and pump beams impact on the spectral bandwidth of the photons. Our results indicate that this parameter is greatly affected by the spatial properties of the detection beam, while not as much by the pump beam. This allows for a simple experimental implementation to control the bandwidth of the biphoton spectra, which only entails modifying the optical configuration to collect the photons. Moreover, we have performed Hong–Ou–Mandel interferometry measurements that also provide the phase of the biphoton wavefunction, and thereby its temporal shape. We explain all these results with a toy model derived under certain approximations, which accurately recovers most of the interesting experimental details.JJMV, JLA, MMF and GMT acknowledge the FIS2017-87363-P project of the Spanish Ministerio de Educación, Cultura y Deporte. NT acknowledges support by the Griffith University, Australia Postdoctoral Fellowship Scheme by the Australian Research Council (ARC) Centre of Excellence CE17010001, and by the Alexander von Humboldt Foundation, Germany .Peer reviewe

Journal of Physics: Conference Series

1203

Optics Letters

Spatial qudits are D-dimensional (≥2D≥2) quantum systems carrying information encoded in the discretized transverse momentum and position of single photons. We present a proof-of-principle demonstration of a method for preparing arbitrary pure states of such systems by using a single phase-only spatial light modulator (SLM). The method relies on the encoding of the complex transmission function corresponding to a given spatial qudit state onto a preset diffraction order of a phase-only grating function addressed at the SLM. Fidelities of preparation above 94% were obtained with this method, which is simpler, less costly, and more efficient than those that require two SLMs for the same purpose.Fil: Solís Prosser, M. A.. Universidad de Concepción; ChileFil: Arias, A.. Universidad de Concepción; Chile. Instituto Tecnológico Metropolitano; ColombiaFil: Varga, Juan José Miguel. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Física; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Rebon, Lorena. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - la Plata. Instituto de Física la Plata. Universidad Nacional de la Plata. Facultad de Ciencias Exactas. Instituto de Física la Plata; ArgentinaFil: Ledesma, Silvia Adriana. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Física; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Iemmi, Claudio Cesar. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Física; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Neves, L.. Universidade Federal do Minas Gerais; Brasi

Symmetry-protection of multiphoton states of light

In this manuscript we analyze the emergence of protected multiphoton states in scattering problems with cylindrical symmetry. In order to do that, we first provide a formal definition of the concept of postselected symmetry-protection. We show that the notion of symmetry-protection is not limited to one- or two-photon states, on the contrary, it can be formally extended to the multiphoton case. In addition, we prove for the case of cylindrical symmetry that all possible multiphoton protected states are constructed from a small set of one- and two-photon states. Finally, we point out possible applications that symmetry-protected states may have in quantum communications, concretely, in the construction of decoherence-free subspaces.JLA, MMF, JJMV and GMT acknowledge the FIS2017-87363-P project of the Spanish Ministerio de Educación, Cultura y Deporte. JLA and AGE acknowledge the PID2019-109905GA-C22 project of the Spanish Ministerio de Ciencia, Innovacion y Universidades (MICIU). AGE received funding from the Gipuzkoako Foru Aldundia OF23/2019 (ES) projectand by Eusko Jaurlaritza grant numbers IT1164-19 and KK-2019/00101.Peer reviewe

Scattering of classical and quantum states of light with angular momentum by dielectric micro/nanoresonators

Resumen del trabajo presentado a la NanoSpain Conference, celebrada en Madrid del 17 al 20 de mayo de 2022.Peer reviewe