Measuring spatial correlations of photon pairs by automated raster scanning with spatial light modulators

Paul, Eduardo; Hor-Meyll, M.; Ribeiro, P. H. Souto; Walborn, S. P.

doi:10.1038/srep05337

Cited by 9 publications

(9 citation statements)

References 42 publications

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“…The π-phase step is easily implemented via phase-only spatial light modulators (SLMs) placed in each path. The choice of using a phase edge over amplitude prevents high photon loss during the measurement, making the 2Dπ-measurement an efficient alternative to knife-edge or post-selection slit-based experiments [41,[49][50][51][52][53][54]. Here, we assume the apparent rotational symmetry of the JTMA in the joint (q x , q y ) planes, and scan the π-phase discontinuous profiles for both signal and idler SLMs along the x-axis.…”

Section: B 2dπ-measurementmentioning

confidence: 99%

Characterising and Tailoring Spatial Correlations in Multi-Mode Parametric Downconversion

Srivastav,

Valencia,

Leedumrongwatthanakun

et al. 2021

Preprint

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Photons entangled in their position-momentum degrees of freedom (DoFs) serve as an elegant manifestation of the Einstein-Podolsky-Rosen paradox, while also enhancing quantum technologies for communication, imaging, and computation. The multi-mode nature of photons generated in parametric downconversion has inspired a new generation of experiments on high-dimensional entanglement, ranging from complete quantum state teleportation to exotic multi-partite entanglement. However, precise characterisation of the underlying position-momentum state is notoriously difficult due to limitations in detector technology, resulting in a slow and inaccurate reconstruction riddled with noise. Furthermore, theoretical models for the generated two-photon state often forgo the importance of the measurement system, resulting in a discrepancy between theory and experiment. Here we formalise a description of the two-photon wavefunction in the spatial domain, referred to as the collected joint-transverse-momentum-amplitude (JTMA), which incorporates both the generation and measurement system involved. We go on to propose and demonstrate a practical and efficient method to accurately reconstruct the collected JTMA using a simple phase-step scan known as the 2Dπ-measurement. Finally, we discuss how precise knowledge of the collected JTMA enables us to generate tailored high-dimensional entangled states that maximise discretevariable entanglement measures such as entanglement-of-formation or entanglement dimensionality, and optimise critical experimental parameters such as photon heralding efficiency. By accurately and efficiently characterising photonic position-momentum entanglement, our results unlock its full potential for discrete-variable quantum information science and lay the groundwork for future quantum technologies based on multi-mode entanglement.

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Section: B 2dπ-measurementmentioning

confidence: 99%

Characterising and Tailoring Spatial Correlations in Multi-Mode Parametric Downconversion

Srivastav,

Valencia,

Leedumrongwatthanakun

et al. 2021

Preprint

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“…The combination of phase-only SLMs with before-and after-polarization projections is a method to convert the SLM-imprinted phase pattern into the amplitude distribution of the light beam [19]. One advantage of using the amplitude-related encoding instead of phase is that amplitude information can be straightforwardly measured through the intensity distribution and recorded as an image using, e.g., a CCD camera.…”

Section: Optical Computation Schemementioning

confidence: 99%

“…Specifically, we employ a HWP (tilting the polarization in −45 • , i.e., D→H and A→V) and a PBS (filtering only the H component) to project the diagonal component of the field in Eq. ( 4), resulting in [19]:…”

Section: A Connection Between Intensity Measurements and The Target O...mentioning

confidence: 99%

Solving the One-dimensional Distance Geometry Problem by Optical Computing

Hengeveld¹,

Gonçalves²,

Ribeiro³

et al. 2021

Preprint

Self Cite

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Distance geometry problem belongs to a class of hard problems in classical computation that can be understood in terms of a set of inputs processed according to a given transformation, and for which the number of possible outcomes grows exponentially with the number of inputs. It is conjectured that quantum computing schemes can solve problems belonging to this class in a time that grows only at a polynomial rate with the number of inputs. While quantum computers are still being developed, there are some classical optics computation approaches that can perform very well for specific tasks. Here, we present an optical computing approach for the distance geometry problem in one dimension and show that it is very promising in the classical computing regime.

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“…Measurement of the Talbot QuDits in the computational basis can be performed simply by using an array of single photon detectors, single-photon sensitive cameras [34,35], or spatial light modulators [36]. In all of these techniques, registration of a photon at some spatial position indicates one of the basis states |d D .…”

Section: Measurementmentioning

confidence: 99%

Quantum information processing by weaving quantum Talbot carpets

et al. 2015

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Single photon interference due to passage through a periodic grating is considered in a novel proposal for processing D-dimensional quantum systems (quDits) encoded in the spatial degrees of freedom of light. We show that free space propagation naturally implements basic single quDit gates by means of the Talbot effect: an intricate time-space carpet of light in the near field diffraction regime. Adding a diagonal phase gate, we show that a complete set of single quDit gates can be implemented. We then introduce a spatially-dependent beam splitter that allows implementation of controlled operations between two quDits. A new form of universal quantum information processing can then be implemented with linear optics and ancilla photons. Though we consider photons, our scheme should be directly applicable to a number of other physical systems. Interpretation of the Talbot effect as a quantum logic operation provides a beautiful and interesting way to visualize quantum computation through wave propagation and interference.

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Measuring spatial correlations of photon pairs by automated raster scanning with spatial light modulators

Cited by 9 publications

References 42 publications

Characterising and Tailoring Spatial Correlations in Multi-Mode Parametric Downconversion

Characterising and Tailoring Spatial Correlations in Multi-Mode Parametric Downconversion

Solving the One-dimensional Distance Geometry Problem by Optical Computing

Quantum information processing by weaving quantum Talbot carpets

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