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Optical vortex knots - one photon at a time.

Tempone-Wiltshire SJ, Johnstone SP, Helmerson K - Sci Rep (2016)

Bottom Line: The particle-wave duality of light should also apply to complex three dimensional optical fields formed by multi-path interference, however, this has not been demonstrated.Here we observe particle-wave duality of a three dimensional field by generating a trefoil optical vortex knot - one photon at a time.This result demonstrates a fundamental physical principle, that particle-wave duality implies interference in both space (between spatially distinct modes) and time (through the complex evolution of the superposition of modes), and has implications for topologically entangled single photon states, orbital angular momentum multiplexing and topological quantum computing.

View Article: PubMed Central - PubMed

Affiliation: School of Physics and Astronomy, Monash University, Victoria 3800, Australia.

ABSTRACT
Feynman described the double slit experiment as "a phenomenon which is impossible, absolutely impossible, to explain in any classical way and which has in it the heart of quantum mechanics". The double-slit experiment, performed one photon at a time, dramatically demonstrates the particle-wave duality of quantum objects by generating a fringe pattern corresponding to the interference of light (a wave phenomenon) from two slits, even when there is only one photon (a particle) at a time passing through the apparatus. The particle-wave duality of light should also apply to complex three dimensional optical fields formed by multi-path interference, however, this has not been demonstrated. Here we observe particle-wave duality of a three dimensional field by generating a trefoil optical vortex knot - one photon at a time. This result demonstrates a fundamental physical principle, that particle-wave duality implies interference in both space (between spatially distinct modes) and time (through the complex evolution of the superposition of modes), and has implications for topologically entangled single photon states, orbital angular momentum multiplexing and topological quantum computing.

No MeSH data available.


Related in: MedlinePlus

Left: Optical set-up for a ‘which path’ measurement.The SLM contains two holograms (shown in the inset and provided as supplementary material) side by side. The laser beam is split into two and passes through a chopper blade (CB), which ensures that photon’s are present along the optical path from only one of the two holograms at any given time. The two beam paths are later recombined and imaged onto the camera. Right: ‘Which path’ measurements of the optical field. The three columns shown contain the theoretical intensity patterns of the knotted optical field (left), the intensity patterns resulting from the unchopped beams (centre) and from the chopped beams (right). These images are taken at three different transverse planes along the beam path (positions are indicated in centimetres). A normalised cross correlation of the data (centre and right) with simulation (left) shows a higher correlation of the knot with the unchopped optical field, with an average peak value of 0.89, as opposed to when the beam is chopped which yields an average peak value of 0.62.
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f3: Left: Optical set-up for a ‘which path’ measurement.The SLM contains two holograms (shown in the inset and provided as supplementary material) side by side. The laser beam is split into two and passes through a chopper blade (CB), which ensures that photon’s are present along the optical path from only one of the two holograms at any given time. The two beam paths are later recombined and imaged onto the camera. Right: ‘Which path’ measurements of the optical field. The three columns shown contain the theoretical intensity patterns of the knotted optical field (left), the intensity patterns resulting from the unchopped beams (centre) and from the chopped beams (right). These images are taken at three different transverse planes along the beam path (positions are indicated in centimetres). A normalised cross correlation of the data (centre and right) with simulation (left) shows a higher correlation of the knot with the unchopped optical field, with an average peak value of 0.89, as opposed to when the beam is chopped which yields an average peak value of 0.62.

Mentions: We further verified that the distribution of single photons produces the knotted nodal structure via a ‘which path’ measurement. The optical set up used for this measurement, shown on the left in Fig. 3, involves splitting the optical path at the SLM so that each path only passes through one half of the SLM screen. This path separation allows a chopper wheel to be inserted just after the SLM, which at any given time blocks one of the two paths.


Optical vortex knots - one photon at a time.

Tempone-Wiltshire SJ, Johnstone SP, Helmerson K - Sci Rep (2016)

Left: Optical set-up for a ‘which path’ measurement.The SLM contains two holograms (shown in the inset and provided as supplementary material) side by side. The laser beam is split into two and passes through a chopper blade (CB), which ensures that photon’s are present along the optical path from only one of the two holograms at any given time. The two beam paths are later recombined and imaged onto the camera. Right: ‘Which path’ measurements of the optical field. The three columns shown contain the theoretical intensity patterns of the knotted optical field (left), the intensity patterns resulting from the unchopped beams (centre) and from the chopped beams (right). These images are taken at three different transverse planes along the beam path (positions are indicated in centimetres). A normalised cross correlation of the data (centre and right) with simulation (left) shows a higher correlation of the knot with the unchopped optical field, with an average peak value of 0.89, as opposed to when the beam is chopped which yields an average peak value of 0.62.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4834479&req=5

f3: Left: Optical set-up for a ‘which path’ measurement.The SLM contains two holograms (shown in the inset and provided as supplementary material) side by side. The laser beam is split into two and passes through a chopper blade (CB), which ensures that photon’s are present along the optical path from only one of the two holograms at any given time. The two beam paths are later recombined and imaged onto the camera. Right: ‘Which path’ measurements of the optical field. The three columns shown contain the theoretical intensity patterns of the knotted optical field (left), the intensity patterns resulting from the unchopped beams (centre) and from the chopped beams (right). These images are taken at three different transverse planes along the beam path (positions are indicated in centimetres). A normalised cross correlation of the data (centre and right) with simulation (left) shows a higher correlation of the knot with the unchopped optical field, with an average peak value of 0.89, as opposed to when the beam is chopped which yields an average peak value of 0.62.
Mentions: We further verified that the distribution of single photons produces the knotted nodal structure via a ‘which path’ measurement. The optical set up used for this measurement, shown on the left in Fig. 3, involves splitting the optical path at the SLM so that each path only passes through one half of the SLM screen. This path separation allows a chopper wheel to be inserted just after the SLM, which at any given time blocks one of the two paths.

Bottom Line: The particle-wave duality of light should also apply to complex three dimensional optical fields formed by multi-path interference, however, this has not been demonstrated.Here we observe particle-wave duality of a three dimensional field by generating a trefoil optical vortex knot - one photon at a time.This result demonstrates a fundamental physical principle, that particle-wave duality implies interference in both space (between spatially distinct modes) and time (through the complex evolution of the superposition of modes), and has implications for topologically entangled single photon states, orbital angular momentum multiplexing and topological quantum computing.

View Article: PubMed Central - PubMed

Affiliation: School of Physics and Astronomy, Monash University, Victoria 3800, Australia.

ABSTRACT
Feynman described the double slit experiment as "a phenomenon which is impossible, absolutely impossible, to explain in any classical way and which has in it the heart of quantum mechanics". The double-slit experiment, performed one photon at a time, dramatically demonstrates the particle-wave duality of quantum objects by generating a fringe pattern corresponding to the interference of light (a wave phenomenon) from two slits, even when there is only one photon (a particle) at a time passing through the apparatus. The particle-wave duality of light should also apply to complex three dimensional optical fields formed by multi-path interference, however, this has not been demonstrated. Here we observe particle-wave duality of a three dimensional field by generating a trefoil optical vortex knot - one photon at a time. This result demonstrates a fundamental physical principle, that particle-wave duality implies interference in both space (between spatially distinct modes) and time (through the complex evolution of the superposition of modes), and has implications for topologically entangled single photon states, orbital angular momentum multiplexing and topological quantum computing.

No MeSH data available.


Related in: MedlinePlus