Optical polarization

About: Optical polarization is a research topic. Over the lifetime, 13992 publications have been published within this topic receiving 244284 citations.

Flat Optics: Controlling Wavefronts With Optical Antenna Metasurfaces

Abstract: Conventional optical components rely on the propagation effect to control the phase and polarization of light beams. One can instead exploit abrupt phase and polarization changes associated with scattered light from optical resonators to control light propagation. In this paper, we discuss the optical responses of anisotropic plasmonic antennas and a new class of planar optical components (“metasurfaces”) based on arrays of these antennas. To demonstrate the versatility of metasurfaces, we show the design and experimental realization of a number of flat optical components: 1) metasurfaces with a constant interfacial phase gradient that deflect light into arbitrary directions; 2) metasurfaces with anisotropic optical responses that create light beams of arbitrary polarization over a wide wavelength range; 3) planar lenses and axicons that generate spherical wavefronts and nondiffracting Bessel beams, respectively; and 4) metasurfaces with spiral phase distributions that create optical vortex beams of well-defined orbital angular momentum.

Intensity discrimination of optical pulses with birefringent fibers.

Abstract: An intensity discriminator for optical pulses can be made with a birefringent fiber. Such a discriminator would be useful for separating the intense subpicosecond pulses formed by solitonlike compression from the weaker uncompressed background. The discriminator utilizes an intensity-dependent state of polarization out of the fiber.

Photonic polarization gears for ultra-sensitive angular measurements

Abstract: Quantum metrology bears a great promise in enhancing measurement precision, but is unlikely to become practical in the near future. Its concepts can nevertheless inspire classical or hybrid methods of immediate value. Here we demonstrate NOON-like photonic states of m quanta of angular momentum up to m=100, in a setup that acts as a 'photonic gear', converting, for each photon, a mechanical rotation of an angle θ into an amplified rotation of the optical polarization by mθ, corresponding to a 'super-resolving' Malus' law. We show that this effect leads to single-photon angular measurements with the same precision of polarization-only quantum strategies with m photons, but robust to photon losses. Moreover, we combine the gear effect with the quantum enhancement due to entanglement, thus exploiting the advantages of both approaches. The high 'gear ratio' m boosts the current state of the art of optical non-contact angular measurements by almost two orders of magnitude.

Two-Pole Caustic Model for High-Energy Light Curves of Pulsars

Abstract: We present a new model of high-energy light curves from rotation-powered pulsars. The key ingredient of the model is the gap region (i.e., the region where particle acceleration is taking place and high-energy photons originate) that satisfies the following assumptions: (1) the gap region extends from each polar cap to the light cylinder; (2) the gap is thin and confined to the surface of last open magnetic-field lines; (3) photon emissivity is uniform within the gap region. The model light curves are dominated by strong peaks (either double or single) of caustic origin. Unlike other pulsar models with caustic effects, the double peaks arise from a crossing two caustics, each of which is associated with a different magnetic pole. The generic features of the light curves are consistent with the observed characteristics of pulsar light curves: (1) the most natural (in terms of probability) shape consists of two peaks (separated by 0.4 to 0.5 in phase for large viewing angles); (2) the peaks possess well-developed wings; (3) there is a bridge (interpeak) emission component; (4) there is a nonvanishing off-pulse emission level; (5) the radio pulse occurs before the leading high-energy peak. The model is well suited for four gamma-ray pulsars?Crab, Vela, Geminga, and B1951+32?with double-peak light curves exhibiting the peak separation of 0.4 to 0.5 in phase. Here we apply the model to the Vela pulsar. Moreover, we indicate the limitation of the model in accurate reproducing of the light curves with single pulses and narrowly separated (about 0.2 in phase) pulse peaks. We also discuss the optical polarization properties for the Crab pulsar in the context of the two-pole caustic model.