Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

Optics Express

Refractive elements for the measurement of the orbital angular momentum of a single photon

Martin P. J. Lavery, David J. Robertson, Gregorius C. G. Berkhout, Gordon D. Love, Miles J. Padgett, Johannes Courtial

Published Jan 17, 2012• 278 citations
Publisher

Abstract

We have developed a mode transformer comprising two custom refractive optical elements which convert orbital angular momentum states into transverse momentum states. This transformation allows for an efficient measurement of the orbital angular momentum content of an input light beam. We characterise the channel capacity of the system for 50 input modes, giving a maximum value of 3.46 bits per photon. Using an electron multiplying CCD (EMCCD) camera with a laser source attenuated such that on average there is less than one photon present within the system per measurement period, we demonstrate that the elements are efficient for the use in single photon experiments.

DOI
10.1364/oe.20.002110

Related papers

Measuring the orbital angular moment of light with high optical efficiency

Martin P. J. Lavery, David J. Robertson, Johannes Courtial +3 more

We have produced custom refractive optical elements which transform orbital angular momentum states into linear direction states. This transformation allows for an efficient measurement of the orbital angular momentum content of an input light beam.

International Conference on Quantum Information•Jan 1, 2011•1 citation

The efficient sorting of light's orbital angular momentum for optical communications

Martin P. J. Lavery, David Roberston, Mehul Malik +4 more

The desire to increase the amount of information that can be encoded onto a single photon has driven research into many areas of optics. One such area is optical orbital angular momentum (OAM) [1]. These beams have helical phasefronts and carry an orbital angular momentum of mbar per photon, where the integer m is unbounded, giving a large state space in which to encode information. We recently developed a telescope system comprising two bespoke refractive optical elements to transform OAM states into transverse momentum states [2]. This is achieved by mapping the azimuthal position of the input plane to the lateral position in the output [3]. A mapping of this type transforms a set of concentric rings at the input plane into a set of parallel lines in the output plane. A lens can then separate the resulting transverse momentum states into specified lateral positions, allowing for the efficient measurement of multiple OAM states simultaneously. Separating OAM states in this way presents an opportunity for this larger alphabet to improve the data capacity of a free space link and has potential application in both the classical and quantum regimes. We will present our latest design, increasing the bandwidth of measurable states to over 50 OAM modes. In such a system we study the crosstalk introduced by a thin phase turbulence, showing that turbulence similarly degrades the purity of all the modes within this range.

Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE•Nov 19, 2012•12 citations

Fourier Transform of the Orbital Angular Momentum of a Single Photon

Jaroslav Kysela, Xiaoqin Gao, Borivoje Dakić

Optical networks implementing single-qudit quantum gates may exhibit superior properties to those for qubits as each optical element in the network can work in parallel on many optical modes simultaneously. We present a class of such networks that implements in a deterministic and efficient way the quantum Fourier transform (QFT) in an arbitrarily high dimension. These networks redistribute the initial quantum state into the orbital angular momentum (OAM) and path degrees of freedom and offer two modes of operation. Either the OAM-only QFT can be implemented, which uses the path as an internal auxiliary degree of freedom, or the path-only QFT is implemented, which uses the OAM as the auxiliary degree of freedom. The resources for both schemes scale linearly $O(d)$ with the dimension $d$ of the system, beating the best known bounds for the path-encoded QFT. While the QFT of the orbital-angular-momentum states of single photons has been applied in a multitude of experiments, these schemes require specially designed elements with nontrivial phase profiles. In contrast, we propose a different approach that utilizes only conventional optical elements.

arXiv:2004.12788•Physical Review Applied•Sep 14, 2020•15 citations

Mode sorter and detector based on photon orbital angular momentum

Baha Jassemnejad, A. Bohannan, John Lekki +1 more

Photons were generated possessing orbital angular momentum (OAM) in the form of Laguerre-Gaussian (LG) laser modes. Three Mach-Zehnder interferometer systems, with the use of Dove prisms, were constructed to sort and detect the LG modes based on their OAM state. Successful generating, sorting, and detecting of LG modes is the first step towards information encoding and decoding via lasers. It is possible to generate many LG modes, which can be orthogonally decoded. With many modes to encode information with it is possible to transfer more than one bit of information with a single photon using LG encoding. An experimental test of this concept was performed by demonstrating the generation and sorting of LG modes with attenuated intensities averaging below one photon passing through the system at a time. In summary, generating, sorting, and low-power detecting of specific LG modes were all demonstrated.

Optical Engineering•May 1, 2008•10 citations

Efficient full state tomography of the orbital angular momentum states of light using Helicity sorter

Joel M. Sunil, Goyal, Sandeep K.

Orbital angular momentum (OAM) of light is a promising degree of freedom for quantum communication and quantum computation. However, efficient methods to transform and measure OAM modes are still not available readily. Here, we propose a method for full quantum state tomography for arbitrary OAM states of light. The key component in our scheme is the helicity sorter, a device that can sort OAM modes of a light beam based on their Helicity. We present two setups to implement the Helicity sorted, one requires $\mathcal{O}(N)$ number of optical elements for $2^N$ OAM modes, and the other uses spatial light modulators and is independent of the number of OAM modes. Ours is the first method to provide the efficient and scalable full quantum state tomography of the OAM modes and can be extremely important for quantum communication and quantum computation.

arXiv:2112.06277•Dec 12, 2021•0 citations

Measuring the orbital angular momentum of light

Miles J. Padgett, Martin P. J. Lavery, Gregorius C. G. Berkhout +2 more

We report a new simple optical system for the highly efficient measurement of the Orbital Angular Momentum States of Light. It uses an image reformatter to map each input state onto a different lateral position in the output aperture. This, near perfect, separation of states potentially makes available the high information capacity of OAM in both classical and quantum applications.

Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE•Jan 13, 2011•2 citations
We have developed a mode transformer comprising two custom refractive optical elements which convert orbital angular momentum states into transverse momentum states. This transformation allows for an efficient measurement of the orbital angular momentum content of an input light beam. We characterise the channel capacity of the system for 50 input modes, giving a maximum value of 3.46 bits per photon. Using an electron multiplying CCD (EMCCD) camera with a laser source attenuated such that on average there is less than one photon present within the system per measurement period, we demonstrate that the elements are efficient for the use in single photon experiments.
The desire to increase the amount of information that can be encoded onto a single photon has driven research into many areas of optics. One such area is optical orbital angular momentum (OAM) [1]. These beams have helical phasefronts and carry an orbital angular momentum of mbar per photon, where the integer m is unbounded, giving a large state space in which to encode information. We recently developed a telescope system comprising two bespoke refractive optical elements to transform OAM states into transverse momentum states [2]. This is achieved by mapping the azimuthal position of the input plane to the lateral position in the output [3]. A mapping of this type transforms a set of concentric rings at the input plane into a set of parallel lines in the output plane. A lens can then separate the resulting transverse momentum states into specified lateral positions, allowing for the efficient measurement of multiple OAM states simultaneously. Separating OAM states in this way presents an opportunity for this larger alphabet to improve the data capacity of a free space link and has potential application in both the classical and quantum regimes. We will present our latest design, increasing the bandwidth of measurable states to over 50 OAM modes. In such a system we study the crosstalk introduced by a thin phase turbulence, showing that turbulence similarly degrades the purity of all the modes within this range.
Optical networks implementing single-qudit quantum gates may exhibit superior properties to those for qubits as each optical element in the network can work in parallel on many optical modes simultaneously. We present a class of such networks that implements in a deterministic and efficient way the quantum Fourier transform (QFT) in an arbitrarily high dimension. These networks redistribute the initial quantum state into the orbital angular momentum (OAM) and path degrees of freedom and offer two modes of operation. Either the OAM-only QFT can be implemented, which uses the path as an internal auxiliary degree of freedom, or the path-only QFT is implemented, which uses the OAM as the auxiliary degree of freedom. The resources for both schemes scale linearly O(d)O(d)O(d) with the dimension ddd of the system, beating the best known bounds for the path-encoded QFT. While the QFT of the orbital-angular-momentum states of single photons has been applied in a multitude of experiments, these schemes require specially designed elements with nontrivial phase profiles. In contrast, we propose a different approach that utilizes only conventional optical elements.
Photons were generated possessing orbital angular momentum (OAM) in the form of Laguerre-Gaussian (LG) laser modes. Three Mach-Zehnder interferometer systems, with the use of Dove prisms, were constructed to sort and detect the LG modes based on their OAM state. Successful generating, sorting, and detecting of LG modes is the first step towards information encoding and decoding via lasers. It is possible to generate many LG modes, which can be orthogonally decoded. With many modes to encode information with it is possible to transfer more than one bit of information with a single photon using LG encoding. An experimental test of this concept was performed by demonstrating the generation and sorting of LG modes with attenuated intensities averaging below one photon passing through the system at a time. In summary, generating, sorting, and low-power detecting of specific LG modes were all demonstrated.
Orbital angular momentum (OAM) of light is a promising degree of freedom for quantum communication and quantum computation. However, efficient methods to transform and measure OAM modes are still not available readily. Here, we propose a method for full quantum state tomography for arbitrary OAM states of light. The key component in our scheme is the helicity sorter, a device that can sort OAM modes of a light beam based on their Helicity. We present two setups to implement the Helicity sorted, one requires O(N)\mathcal{O}(N)O(N) number of optical elements for 2N2^N2N OAM modes, and the other uses spatial light modulators and is independent of the number of OAM modes. Ours is the first method to provide the efficient and scalable full quantum state tomography of the OAM modes and can be extremely important for quantum communication and quantum computation.