Amplitude and phase sorting of orbital angular momentum states at low light levels

Ariyawansa, Ashan; Figueroa, Edward J.; Brown, Thomas G.

doi:10.1364/optica.409204

Cited by 14 publications

(6 citation statements)

References 45 publications

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“…Note that quantum state tomography via projective measurement becomes challenging when the dimension of the quantum state is not a power of a prime number [24]. Here, we try to tackle the tomographic challenge, in the specific contest of spatially correlated biphoton states, looking for an interferometric approach inspired by digital holography [25][26][27][28][29][30], familiar in classical optics. We show that the coincidence imaging of the superposition of two biphoton states, one unknown and one used as a reference state, allows retrieving the spatial distribution of phase and amplitude of the unknown biphoton wavefunction.…”

Section: Introductionmentioning

confidence: 99%

Interferometric imaging of amplitude and phase of spatial biphoton states

Zia¹,

Nazanin²,

D’Errico³

et al. 2023

Preprint

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High-dimensional biphoton states are promising resources for quantum applications, ranging from highdimensional quantum communications to quantum imaging. A pivotal task is fully characterising these states, which is generally time-consuming and not scalable when projective measurement approaches are adopted. However, new advances in coincidence imaging technologies allow for overcoming these limitations by parallelising multiple measurements. Here, we introduce biphoton digital holography, in analogy to off-axis digital holography, where coincidence imaging of the superposition of an unknown state with a reference one is used to perform quantum state tomography. We apply this approach to single photons emitted by spontaneous parametric down-conversion in a nonlinear crystal when the pump photons possess various quantum states. The proposed reconstruction technique allows for a more efficient (3 order-of-magnitude faster) and reliable (an average fidelity of 87%) characterisation of states in arbitrary spatial modes bases, compared with previously performed experiments. Multi-photon digital holography may pave the route toward efficient and accurate computational ghost imaging and high-dimensional quantum information processing.

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Section: Introductionmentioning

confidence: 99%

Interferometric imaging of amplitude and phase of spatial biphoton states

Zia¹,

Nazanin²,

D’Errico³

et al. 2023

Preprint

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“…Its internal operation depends on the spatial information carried by the incoming mode. 17,18 Figure 1 schematically shows the behavior of a general OAM mode sorter, where several OAM modes with different azimuthal indexes can be sorted at the output of the system.…”

Section: ■ Introductionmentioning

confidence: 99%

All-in-Fiber Dynamically Reconfigurable Orbital Angular Momentum Mode Sorting

Alarcón,

Gómez,

Spegel-Lexne

et al. 2023

ACS Photonics

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The orbital angular momentum (OAM) spatial degree of freedom of light has been widely explored in many applications, including telecommunications, quantum information, and light-based micromanipulation. The ability to separate and distinguish between the different transverse spatial modes is called mode sorting or mode demultiplexing, and it is essential to recover the encoded information in such applications. An ideal d mode sorter should be able to faithfully distinguish between the different d spatial modes, with minimal losses, and have d outputs and fast response times. All previous mode sorters rely on bulk optical elements, such as spatial light modulators, which cannot be quickly tuned and have additional losses if they are to be integrated with optical fiber systems. Here, we propose and experimentally demonstrate, to the best of our knowledge, the first all-in-fiber method for OAM mode sorting with ultrafast dynamic reconfigurability. Our scheme first decomposes the OAM mode in-fiber-optical linearly polarized (LP) modes and then interferometrically recombines them to determine the topological charge, thus correctly sorting the OAM mode. In addition, our setup can also be used to perform ultrafast routing of the OAM modes. These results show a novel and fiber-integrated form of optical spatial mode sorting that can be readily used for many new applications in classical and quantum information processing.

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“…Known techniques to characterize OAM states include demultiplexing based on multi-plane light conversion [62], holographic and optical geometric transformation-based sorters [63][64][65][66][67][68][69][70][71], metasurfaces [51-53, 72, 73], holograms imprinting phase patterns (e.g. from SLMs) followed by single-mode fibers [43,[74][75][76][77], hybrid approaches [78], time-based multiplexing [79][80][81], lenses [82], techniques using Doppler frequency shifts [83][84][85], interferometric, refractive or diffractive schemes [58,59,67,69,70,[86][87][88][89] and weak measurements [90]. Machine learning (ML) methods have also recently proved valuable in the context of the reconstruction of the properties of structured light.…”

Section: Introductionmentioning

confidence: 99%

Enhanced detection techniques of Orbital Angular Momentum states in the classical and quantum regimes

Suprano,

Zia,

Polino

et al. 2022

Preprint

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The Orbital Angular Momentum (OAM) of light has been at the center of several classical and quantum applications for imaging, information processing and communication. However, the complex structure inherent in OAM states makes their detection and classification nontrivial in many circumstances. Most of the current detection schemes are based on models of the OAM states built upon the use of Laguerre-Gauss modes. However, this may not in general be sufficient to capture full information on the generated states. In this paper, we go beyond the Laguerre-Gauss assumption, and employ Hypergeometric-Gaussian modes as the basis states of a refined model that can be used -in certain scenarios -to better tailor OAM detection techniques. We show that enhanced performances in OAM detection are obtained for holographic projection via spatial light modulators in combination with single-mode fibers, and for classification techniques based on a machine learning approach. Furthermore, a three-fold enhancement in the single-mode fiber coupling efficiency is obtained for the holographic technique, when using the Hypergeometric-Gaussian model with respect to the Laguerre-Gauss one. This improvement provides a significant boost in the overall efficiency of OAM-encoded single-photon detection systems. Given that most of the experimental works using OAM states are effectively based on the generation of Hypergeometric-Gauss modes, our findings thus represent a relevant addition to experimental toolboxes for OAM-based protocols in quantum communication, cryptography and simulation.

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Amplitude and phase sorting of orbital angular momentum states at low light levels

Cited by 14 publications

References 45 publications

Interferometric imaging of amplitude and phase of spatial biphoton states

Interferometric imaging of amplitude and phase of spatial biphoton states

All-in-Fiber Dynamically Reconfigurable Orbital Angular Momentum Mode Sorting

Enhanced detection techniques of Orbital Angular Momentum states in the classical and quantum regimes

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