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The structural color from self-assembled metalo-dielectric (In/InP) nanopillars is shown to be polarization sensitive when the axial symmetry is broken. The characteristic dip in the reflection spectra due to resonant absorption is shifted by 90 nm as the polarization of incident light is altered from TE to TM at an incidence angle of 40°. We also show wafer-scale, mask-less fabrication of pillars that are tilted with respect to the substrate, a fast and cost effective method of creating the asymmetrical structures required for polarization sensitivity at normal incidence. A dip shift of 100 nm is observed for 40° tilted nanopillars of average height 380 nm, resulting in a smooth range of colors with changing polarization. FDTD simulations confirm the polarization dependent dip-shift in the resonant absorption wavelength. Furthermore, the field and intensity profiles obtained from the simulations indicate that the resonant absorption dips are due to HE1m-like modal excitations and their shift with respect to the incident angle and polarization leads to the change in perceived color from the tilted nanopillar system.

This work presents the theoretical study on the polarization induced p-type doping of undoped-AlInN graded cladding layers for the deep ultra-violet laser diode (LD) emitting at around 271 nm wavelength. The reference LD consists of 320 nm of linearly graded undoped AlN-Al0.7Ga0.3N layer, while in our LD the graded undoped AlN-Al0.7Ga0.3N layer is replaced by the undoped AlN-Al x In(1−x)N composition graded layers with different x mole fraction from 0.88 to 0.92. The static device resistance for reference LD is ∼28.6 Ω which is reduced to ∼18.38 Ω for AlN-Al0.12In0.88N graded layer at 500 mA. The device resistance has been reduced dramatically by ∼10.2 Ω. The reduction in resistance is attributed to the increased polarization grading in AlN-Al0.12In0.88N. The large polarization grading leads to large hole carrier induction in the layer which increases the p-type conductivity of the undoped AlN-Al0.12In0.88N graded layer. Threshold current for reference LD is 393 mA which has been reduced to 384 mA for AlN-Al0.12In0.88N. The electron leakage has reduced from 0.9 kA cm−2 to 0.11 kA cm−2 at ∼30 kA cm−2 injected current density, whereas the hole transportation has improved from 29.23 kA cm−2 to ∼30 kA cm−2 at ∼30 kA cm−2 injected current density.

We theoretically predicted and experimentally demonstrated the sinusoidal shifts of the 87Rb atom Raman transition frequencies as the polarization vectors of the Raman lasers rotate. We also presented the vanish of the differential light shifts for the magnetic sensitive Raman transitions at some elliptically polarized configurations while no vanish for the magnetic insensitive Raman transition. These results are helpful for the evaluation and elimination of the light shifts induced systemic errors in the atomic magnetometer, atomic interferometer, atomic clock and quantum computing.

We present a simple non-destructive approach for studying the polarization dependence of nonlinear absorption processes in semiconductors. The method is based on measuring the yield of the near UV photoluminescence as a function of polarization and intensity of femtosecond laser pulses. In particular, we investigated the polarization dependence of three photon laser absorption in intrinsic and Al-doped ZnO thin films. Both specimen show stronger emission for linearly polarized excitation compared to circular polarization. The ratios for the three-photon absorption coefficients are about 1.8 and independent of the doping. It is shown that Al-doped films have lower threshold for stimulated emission in comparison to the intrinsic films.

Two-dimensional grating couplers (2D-GCs) that operate with an arbitrary polarization typically exhibit a polarization-dependent loss (PDL) due to the fiber angle tilted to reduce the back reflections at the fiber/grating interface. We numerically analyzed the dependence of the PDL of a 2D-GC in terms of the scatterer arrays and shapes using the three-dimensional finite difference time domain (3D-FDTD) method. The reduction in the PDL of the 2D-GC was realized by slanted arrays and cross-shaped scatterers. We experimentally demonstrated a PDL < 0.3 dB over a 60-nm-wide spectral range and the maximum coupling efficiency (CE) of −3.1 dB in the O-band spectral regime. This relationship of the PDL characteristic was maintained even when the half-etching depth of the 2D-GC deviated in a 200 mm silicon-on-insulator (SOI) wafer.

We prepared a variable optical attenuator (VOA) at λ ~ 1.55 μm using dielectrically actuated liquids. This VOA works in the principle of absorption. Electro-optical characteristics of this VOA were measured in both transmissive and reflective modes. Compared to transmissive mode, reflective mode could offer much larger attenuation without changing other performances. By applying a voltage of 27 Vrms, this VOA could obtain ~19 dB in transmissive mode, and 38 dB in reflective mode. It had insertion loss (IL) of ~0.76 dB with negligible polarization dependent loss (PDL) at various voltages. Due to its competitive features such as voltage actuation, optical isotropy, and large attenuation with zero PDL, this VOA in reflective mode has potential applications in fiber-optic switches, sensing, and other infrared attenuators.

A compact arrayed-waveguide grating (AWG) on the silicon-on-insulator material is designed and fabricated with employment of waveguide-integrated turning mirrors (WITMs). By properly setting the incident angle with the value of 45?, the effective area of the WITM AWG is only 1.15?cm?1.15?cm with the arrayed waveguide area of 0.6?cm?0.6?cm. The crosstalk of the fabricated 1?6 AWG is better than -19?dB. The on-chip insertion loss is about -8.8?dB and the output nonuniformity is less than 0.6?dB. The polarization-dependent central wavelength shift is about 0.048?nm and the polarization dependent loss is neglectable.

A metamaterial comprised of asymmetrically arranged Ag nanoprisms has been proposed and investigated in this paper. The metamaterial shows a polarization dependent PIT effect. The metamaterial with its periodic length along a y-axis less than 400 nm shows two tunable transmission dips. When the periodicity is increased above 400 nm, the metamaterial shows three adjustable transmission dips against the polarization state. By choosing different wavelengths of incident light, the metamaterial can be used as plasmonic Boolean logic gates. The working wavelengths of these plasmonic devices can then be adjusted by controlling the fillet radius of Ag nanoprism in metamaterial. These results offer great potential in developing polarization dependent tunable plasmonic information processing devices.

Polarization-dependent Raman spectroscopic methods are presented for extracting the integrated intensities of the first-order Si-Si, Si-Ge and Ge-Ge modes in Si1-x Gex . In unpolarized spectra, these modes are distorted by a broad background causing anomalies in their apparent intensities, as derived by standard curve-fitting techniques, which can amount to 300%. The background is strongly polarization dependent. However, the methods described here are successful in minimizing the background in the Raman spectrum and, as a result, the relative intensities measured in the parallel and crossed polarizations differ by less than about 20%. Consequently, the protocols could be developed into process-control techniques for rapid determination of alloy composition (x ) and strain in Si1-x Gex . Additional weak features are revealed when the Raman scattering geometry is altered from a configuration where the first-order optical phonons are allowed to one in which they are forbidden.

A simple general analysis of the insertion loss (diffraction efficiency, or gain) of a linear, deterministic or non-deterministic, optical system as a function of the state of polarization of incident quasi-monochromatic light is presented using the Stokes vector-Mueller matrix description and the associated geometrical interpretation in the Poincare sphere space. A scalar and a vector differential insertion loss (DIL) are defined that determine the intensity transmittance of the optical system for the unpolarized and totally polarized components of an incident partially polarized light beam, respectively. The insertion loss is maximum and minimum when the incident light is totally polarized in a pair of orthogonal states along the straightline extension of the DIL vector, and is constant for all states in a plane normal to the DIL vector, on and within the circle of intersection of the plane with the Poincare sphere. Finally, some results are presented of the measured components of the DIL vectors of a grating that diffracts light into several orders.

Specific patterns determined by the polarization in the retroreflected light from weakly scattering media were investigated. A simple model is developed to account for the observed characteristics of the patterns. Low-order scattering events are considered to be responsible for the occurrence of the patterns. Geometrical and statistical depolarizations as well as the volume fraction of scatterers were taken into account. The theoretical model considered here describes properly the features of the observed patterns.

We report the orbital character of the Fermi surfaces for the Fe-based superconductor LiFeAs using the polarization-dependent three-dimensional angle-resolved photoemission spectroscopy and the angular-dependent dipole selection rule analysis. The evaluated orbital character is well reproduced by the band calculation. The results demonstrate that the polarization-dependent ARPES combined with the selection rule analysis is useful to identify the orbital character of the Fe-based unconventional superconductivity.

We numerically analyze the polarization-fluctuation induced bias error in a resonator fiber optic gyro (R-FOG) with twin 90° polarization-axis rotated splices in the polarization maintaining fiber (PMF) resonator, especially when polarization dependent loss (PDL) exists inside the resonator. Simulation results indicate that the twin 90° polarization-axis rotated splicing method can effectively suppress the polarization-fluctuation induced bias error in an R-FOG, when the length difference of the fiber segments between the two splicing points is set around a half of the beat-length of the PMF. It is also shown that such an R-FOG is still tolerant to PDL if the polarization crosstalk in the resonator is low, although PDL degrades the performance of the R-FOG.

The photonic band structure and circular-polarization dependence of the transmission properties of cholesteric blue phase II were analyzed using a finite-difference time-domain method based on a double-twist cylinder model. The polarization dependence of the calculated band structure was not recognized in the same manner as that in previous studies. However, it can be clearly observed that the calculated transmission spectra depend on the circular polarization; this result agrees well with experimental results. On the basis of the circular-polarization dependence of the transmission spectra in the case of a thick sample, it can be indicated that a total reflection band appears in the selective reflection band.

Adsorption behavior of CS2 molecule on O-, S- and C-precovered Ni(100) surfaces has been studied by polarization dependent S K-edge XANES. The adsorption behavior changes significantly with the precovered elements of O, S and C, though the adsorption site and coverage are the same; CS2 molecule does not dissociate on O- or S-precovered surface at 100K and lies nearly parallel to the surface even in the multilayer, and does dissociate on C-precovered surface. Both the electronic and geometric effects of precovered elements on the inhibition of dissociation are discussed.

The trajectories of the reflected and transmitted beams in the oblique tunnel effect in optics are studied. It is shown that both beams are parallel displaced away from their commonly accepted geometrical trajectories. When the gap tends to infinite, one obtains the ordinary Goos and Hanchen effect. When the gap goes from infinite to zero, the maximum in the parallel displacements of the reflected and transmitted beams is transferred from critical incidence to grazing incidence. The effect is polarization dependent, so that in the general case of random polarization there will be a splitting of both the transmitted and reflected beams.

The polarization dependent gain in quantum well lasers reported previously is explained theoretically in terms of the polarization dependence of momentum matrix elements related to conduction-to-heavy hole and conduction-to-light hole band transitions.