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Register a new userExperimental observation of polarization-dependent optical vortex beams
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Added by
Sarayut Deachapunya
Publication date
2016
fields
Physics
and research's language is
English
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We report the experimental demonstration of the induced polarization-dependent optical vortex beams. We use the Talbot configuration as a method to probe this effect. In particular, our simple experiment shows the direct measurement of this observation. Our experiment can exhibit clearly the combination between the polarization and orbital angular momentum (OAM) states of light. This implementation might be useful for further studies in the quantum system or quantum information.
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We predict and experimentally observe three-dimensional microscale nonparaxial optical bottle beams based on the generation of a caustic surface under revolution. Such bottle beams exhibit high contrast between the surrounding surface and the effectively void interior. Via caustic engineering we can precisely control the functional form of the high intensity surface to achieve microscale bottle beams with longitudinal and transverse dimensions of the same order of magnitude. Although, in general, the phase profile at the input plane can be computed numerically, we find closed form expressions for bottle beams with various type of surfaces both in real and in the Fourier space.
Secret sharing is the art of securely sharing information between more than two people in such a way that its reconstruction requires the collaboration of a certain number of parties. Entanglement-based secret sharing schemes which utilise multi-particle entanglement are limited by their scalability. Recently, a high-dimensional single photon secret sharing protocol was proposed which has impressive advantages in scalability. However, the experimental realisation of this protocol remains elusive. Here, by taking advantage of the high-dimensional Hilbert space for orbital angular momentum and using Perfect Vortex beams as their carriers, we present a proof-of-principle implementation of a high-dimensional single photon quantum secret sharing scheme. We experimentally implemented this scheme for 10 participants in $d=11$ dimensions and show how it can be easily scaled to higher dimensions and any number of participants.
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Weyl fermions are hypothetical two-component massless relativistic particles in three-dimensional (3D) space, proposed by Hermann Weyl in 1929. Their band-crossing points, called Weyl points, carry a topological charge and are therefore highly robust. There has been much excitement over recent observations of Weyl points in microwave photonic crystals and the semimetal TaAs. Here, we report on the first experimental observation of Weyl points of light at optical frequencies. These are also the first observations of type-II Weyl points for photons, which have strictly positive group velocity along one spatial direction. We use a 3D structure consisting of laser-written waveguides, and show the presence of type-II Weyl points by (1) observing conical diffraction along one axis when the frequency is tuned to the Weyl point; and (2) observing the associated Fermi arc surface states. The realization of Weyl points at optical frequencies allow these novel electromagnetic modes to be further explored in the context of linear, nonlinear, and quantum optics.
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