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Here a 1×5 microfluidic optical switch using double drives is proposed. It has a simple structure and ignorable polarization dependent loss. First, the switch with the straight waveguide structure ...

Terahertz technology can be used in sensing and communication applications. We designed a polarization-sensitive photodetector specially for Terahertz frequency based on cross-shaped graphene sheet. The shaped graphene excites localized surface plasmon which can enhance the absorption of incident light. From the Finite Difference Time Domain Solutions (FDTD), we figured out that transmission of incident light relates to the size of photodetector, polarization angle and physical properties of graphene such as chemical potential and layers. The transmission can be tuned as low as 8.3 ×10-5 when we set the size at 14×6µm and 14×5µm for two different graphene pieces and polarization angle as 0°, at room temperature. This device we designed can absorb Terahertz at a wavelength around 126 µm, which can be used in THz application applied in future high-tech communication or safety inspection.

In this paper, an eight-shaped polarization-dependent electromagnetic bandgap (ES-PDEBG) structure is proposed. The unit cell of ES-PDEBG structure consists of an outer eight-shaped EBG patch with two inner square patches and three vias. Surface wave bandgap and reflection phase characteristics have been studied for the proposed structure. From the measurement results, two surface wave bandgaps with center frequencies 3.42 and 5.88 GHz are observed along the X-direction, and one surface wave bandgap with center frequency 3.69 GHz is observed along the Y-direction. The refection phase bandgap of the proposed structure is centered at 5.61 and 3.31 GHz for x- and y-polarized incident plane waves, respectively. Furthermore, the application of the proposed structure as polarization reflector is presented. The study demonstrates that the structure can act as dual-band in-polarization reflector for circularly polarized waves. In addition, incident linearly polarized waves are reflected as circularly polarized waves in four operating bands.

Photocurrent production in the quasi-one-dimensional transition metal trichalcogenides, TiS3(001) and ZrS3(001), was exam-ined using polarization dependent scanning photocurrent microscopy. The pho...

We experimentally investigate the polarization dependence of the optical properties of single-mode polymer optical waveguides. We compare two types of waveguides composed of the same polymer materials: step-index square-core waveguides fabricated using the direct curing method and graded-index (GI) circular-core waveguides fabricated using the Mosquito method. We demonstrate that the GI circular-core single-mode waveguides exhibit remarkably small dependence of optical loss on the polarization angle, which is less than 0.1 dB polarization dependent loss (PDL) at both 1310 and 1550 nm wavelengths. This steady polarization property is attributed to the material stress free to the composing polymers during the fabrication process of the Mosquito method and to parabolic GI profile formed in symmetric circular core.

Traditional polarization modulations suffer from polarization dependent loss (PDL) which affects the the bit error rate (BER) performance. To solve this problem, a polarization M-ary differential chaos shift keying (P-MDCSK) modulation is proposed rather than the conventional MDCSK in this paper. In the proposed scheme, the reference signals are transmitted with polarization states first, and then the information bearing signals are modulated by selecting both phase and polarization states. The union bound of BER expression of the proposed scheme is derived and verified by simulations over both additive white Gaussian noise (AWGN) and multipath Rayleigh fading channels. Results show that the BER performance of the proposed scheme is better than that of other corresponding traditional schemes with a low computational complexity.

We propose a planarized optical waveguide structure functionalized with 2D materials that exhibits strong polarization dependent light interaction. Numerical study on both TE – and TM-polarized lig...

C- and L-band polarization insensitive 1×12 AWG with 100GHz channel-spacing is fabricated on SOI. Results show

International audience; We propose the design of a tubular phononic crystal (TPC) for the purpose of sensing the physical properties of a liquid filling the hollow part of the tube. The TPC is constituted by a periodic repetition of washers along a hollow pipe with the advantage of avoiding any perturbation of a flowing fluid by any element inside the tube. Using finite element simulations, we demonstrate the existence of complete as well as polarization dependent bandgaps inside which one can design localized modes associated with defects. The most sensitive cavity to the liquid sound velocity is found to be constituted by a Fabry-Perot (F-P)

A model is proposed for the polarization dependent nonlinear pulse propagation in multimode fiber. Based on this model, the effects of polarization on the nonlinear modal interaction, including the spatial beam self-cleaning, are analyzed.

One of the most important research topic in optics and photonics is the design of metasurfaces to substitute conventional optical elements that demonstrate unprecedented merits in terms of performance and form factor. In this context, full-space control of metasurfaces that makes it possible to manipulate scattered light in transmission and reflection spaces simultaneously, is proposed as the next-generation scheme in optics, with a potential for applications such as 360° holographic images and novel optical systems. However, previously designed metasurfaces lacked functionality because the desired operation occurs under preconditioned light; therefore, they are difficult to use in real applications. Here, we present a design method that enables polarization-dependent full-space control, in which two independent and arbitrary phase profiles can be addressed to each space. Upon introducing a phase gradient value to realize the critical angle condition, conversion of transmissive into reflective operation is realized. Then, rectangular nanopillars are utilized to facilitate polarization beam splitting with the desired phase. Three samples were fabricated and measured based on the proposed scheme.

A silicon nitride waveguide crossing based on multimode-interference is designed and fabricated. By optimizing the structure parameters with finite difference time domain method, 0.3 dB insertion loss and −75 dB crosstalk at 1550 nm are obtained. Then the designed waveguide crossing is fabricated based on the double strip silicon nitride waveguide. The measured results show the insertion loss and crosstalk are about 0.6 dB and below −42 dB, respectively, in the wavelength range of 1520 nm ∼ 1640 nm with low polarization dependence. The waveguide crossing could be a key building block for the silicon nitride waveguide platform.

We provide through numerical simulations new insights on the polarization-dependent loss (PDL)-induced variability of the signal-to-noise ratio (SNR) in dual-polarization coherent systems when Kerr nonlinearity is significant. We show that the interplay between PDL and nonlinearities provides an SNR distribution broader than the one induced by PDL in the only presence of amplified spontaneous emission noise. Such a broadening is missed by handy state-of-art models as the reverse channel method (RCM) that do not account for fiber nonlinearity, thus resulting inaccurate to estimate the SNR variability at practical launch powers. We show that such an inaccuracy persists even by considering in the RCM the nonlinear noise contribution. We show that the SNR distribution broadening in the presence of fiber nonlinearity is the result of a change in dynamics between the performance of those that can be identified for each PDL draw as best- and worst-performing polarization tributaries. By numerically decoupling the main contributions to fiber nonlinearity we also identify the nonlinear effects responsible for such a change of dynamics. Finally, we qualitatively validate our findings by mean of an experimental result.

In this paper, the general characteristics of the polarization-dependent tuning property and sensitivity optimization of the graphene integrated tilted fiber Bragg grating (TFBG) are investigated theoretically. The tuning mechanism of the graphene on mode characteristics and transmission spectrum is thoroughly explored. The results reveal that the graphene induces a stronger influence on the s-polarized mode than its p-polarized counterpart, but the TFBGs with or without graphene in all the polarized states have nearly the same wavelength sensitivity ( $\sim \text{540}\; \text{nm/RIU}$ in average). In contrast, the resonance strength is highly dependent on the tunable state of the graphene, especially for the s-polarized case. In consequence, the normalized power response is increased in the low refractive index region. More importantly, the s-polarized leaky mode resonance that is ignored for regular TFBGs is significantly enhanced (by increasing field content in the fiber region and decreasing the confinement loss) whereas the guided counterpart is suppressed greatly by the graphene with lower chemical potential. The sensitivity of up to $ \text{6595.8 dB/RIU}$ (9.17 times higher than that of the regular counterpart) is achieved in response to an extremely small analyte perturbation ( $ \text{10}^{-\text{4}}$ close to 1.333) based on the graphene enhanced leaky mode resonance. This paper provides a novel technique for significantly optimizing the sensing performance of the TFBG, which has great potential in biological and biochemical sensing applications.

The in-vivo elucidation of the molecular mechanisms underlying muscles dysfunction due to aging via non-invasive label free imaging techniques is an important issue with high biological significance. In this study, polarization-dependent second-harmonic generation (PSHG) was used to evaluate structural alterations in the striated muscles during Caenorhabditis elegans lifespan. Young and old wild-type animals were irradiated. The obtained results showed that it was not feasible to detect differences in the structure of myosin that could be correlated with the aging of the worms, via the implementation of the classical, widely used, cylindrical symmetry model and the calculation of the SHG anisotropy values. A trigonal symmetry model improved the extracted results; however, the best outcome was originated from the application of a general model. Myosin structural modifications were monitored via the estimation of the difference in spectral phases derived from discrete Fourier transform analysis. Age classification of the nematodes was achieved by employing both models, proving the usefulness of the usage of PSHG microscopy as a potential diagnostic tool for the investigation of muscle diseases.

Funding Information: The work was funded by the Academy of Finland (Projects 322002, 308393, 310511). The work is part of the Academy of Finland Flagship Programme, Photonics Research and Innovation (PREIN), decisions 320166 and 320165. Publisher Copyright: © 2021 The Author(s). Published by IOP Publishing Ltd on behalf of the Institute of Physics and Deutsche Physikalische Gesellschaft. We study beaming properties of laser light produced by a plasmonic lattice overlaid with organic fluorescent molecules. The crossover from spontaneous emission regime to stimulated emission regime is observed in response to increasing pump fluence. This transition is accompanied by a strong reduction of beam divergence and emission linewidth due to increased degree of spatial and temporal coherence, respectively. The feedback for the lasing signal is shown to be mainly one-dimensional due to the dipolar nature of the surface lattice resonance. Consequently, the beaming properties along x and y directions are drastically different. From the measurements, we obtain the M 2 value along both principal directions of the square lattice as a function of the pump fluence. Our work provides the first detailed analysis of the beam quality in plasmonic lattice lasers and reveals the underlying physical origin of the observed strong polarization dependent asymmetry of the lasing signal.

Metasurfaces open up new avenues for designing planar optics, enabling compact dynamic metadevices. Numerous dynamic strategies have been proposed, among which liquid crystal (LC) based metasurfaces are expected due to the maturity of LC materials. However, existing schemes rarely exploit the polarization manipulation capabilities of metasurfaces and the limited performance hinders the development of practical addressable devices. Here, we demonstrate an electrically tunable multifunctional polarization-dependent metasurface integrated with LCs in the visible range. By a combination of the helicity-dependent metasurface and the birefringent LCs, continuous intensity tuning and switching of two helicity channels are realized. Electrically tunable mono- and multicolor switchable metaholograms and dynamic varifocal metalenses are demonstrated with a simple and performance-enhancing integration scheme. Further, electrically addressable dynamic metasurfaces are achieved. The proposed modulation and integration schemes pave the way for addressable dynamic metasurface devices in various applications, such as space light modulators, light detection and ranging systems, and holographic displays.

Hyperbolic materials offer much wider freedom in designing optical properties of nanostructures than ones with isotropic and elliptical dispersion, both metallic or dielectric. Here, we present a detailed theoretical and numerical study on the unique optical properties of spherical nanoantennas composed of such materials. Hyperbolic nanospheres exhibit a rich modal structure that, depending on the polarization and direction of incident light, can exhibit either a full plasmonic-like response with multiple electric resonances, a single, dominant electric dipole or one with mixed magnetic and electric modes with an atypical reversed modal order. We derive conditions for observing these resonances in the dipolar approximation and offer insight into how the modal response evolves with the size, material composition, and illumination. Specifically, the origin of the magnetic dipole mode lies in the hyperbolic dispersion and its existence is determined by two diagonal permittivity components of different sign. Our analysis shows that the origin of this unusual behavior stems from complex coupling between electric and magnetic multipoles, which leads to very strong scattering or absorbing modes. These observations assert that hyperbolic nanoantennas offer a promising route towards novel light–matter interaction regimes.

Methods for measurement of polarization dependent loss and cross talk of individual few mode fiber components and connected systems are presented. A new method for determining the cross talk of the individual components, from the measurements on the connected system is presented and verified through simulations and measurements. The method is based on Fourier analysis of the wavelength dependent interference of the loss of the system.

We engineer the nonlinear response of multilayered hyperbolic metamaterials systems by employing the optical response of Arsenide semiconductor materials. The photoexcited carriers lead to spectral, temporal, and polarization dependent optical response that is described in this talk. The response is suggestive of generating a transient hyperbolic materials response in this system. Exploration of this response and the use of these materials as a basis for nonlinear metasurfaces will be discussed.

In this paper, the novel patch element shapes with the interdigital and multi-via structures of a mushroom-type metasurface reflector are proposed. The interdigital structure provides a wide reflection phase range by changing the depth of the interdigital fingers. In addition, the multi-via structure provides the reflection phases near +180°. These structures have low polarization dependent properties. The desired reflection angles and sharp far field patterns of the reflected beams were obtained in the simulation results.

We apply a polarization-time pre-coding together with an improved four-dimensional (4D) detection for polarization dependent loss mitigation. By taking advantage of the correlation between the noises, the proposed scheme outperforms state-of-the-art PDL mitigation methods.

Based on the polarization-dependent beam splitter (PDBS), we propose an optical scheme to fuse small-size polarization entangled W states into a large-scale W states. With the present scheme, two $$W_{m+n+t-2}$$ states can be created from an n-qubit W state, an m-qubit W state and a t-qubit W state, and two $$W_{m+n+t+q-3}$$ states can be generated from $$W_m$$ , $$W_n$$ , $$W_t$$ and $$W_q$$ states. In the previous fusion schemes, only one particle from each initial W state is allowed to enter the fusion mechanism, but with the progress of experimental technology, two particles can be extracted. In this case, the W states fusion of our scheme will be realized without any ancillary particles and controlled quantum gate. In addition, compared with the one target W state obtained in previous preparation schemes, our scheme can generate two large-scale W states, which effectively improve the success rate of generating target W state. The ability to generate two target W states makes our scheme have a distinct advantage in preparing W states with larger particle numbers. This preparation mechanism also can be generalized to the case of fusing more different or same particles W states.

We experimentally demonstrate integrated waveguide and micro-ring resonator polarizers incorporating two-dimensional layered graphene oxide films, with a high polarization dependent loss of 53.8 dB and a high polarization extinction ratio of 8.3 dB, respectively.

We present a heterogeneous GaAs-based quantum dot (QD) avalanche photodiode (APD) on silicon with a record-high gain-bandwidth product (GBP) of 300 GHz and open eye diagrams up to 15 Gb/s. The polarization dependence of gain, responsivity, and bandwidth has been investigated for the first time.

Nonlinear optical imaging techniques have been widely used to reveal biological structures for accurate diagnosis at the cellular as well as the tissue level. In the present study, polarization-dependent second-harmonic generation (PSHG) was used to determine collagen orientation in breast cancer biopsy tissues (grades 0, I, II and III). The obtained data were processed using fast Fourier transform (FFT) analysis, while second-harmonic generation (SHG) anisotropy and the "ratio parameter" values were also calculated. Such measurements were shown to be able to distinguish collagen structure modifications in different cancer grades tested. The analysis presented herein suggests that PSHG imaging could provide a quantitative evaluation of the tumor state and the distinction of malignant from benign breast tissues. The obtained results also allowed the development of a biophysical model, which can explain the aforementioned differentiations and is in agreement with the simulations relating the SHG anisotropy values with the mechanical tension applied to the collagen during cancer progression. The current approach could be a step forward for the development of new, nondestructive, label free optical diagnostic tools for cancer reducing the need of recalls and unnecessary biopsies, while potentially improving cancer detection rates.

Metal nanostructures offer exciting ways to manage light at the nanoscale exploited in fields such as imaging, sensing, energy conversion, and information processing. The optical response of the metallic architectures can be engineered to exhibit photonic properties that span from plasmon resonances to more complex phenomena such as negative refractive index, optical chirality, artificial magnetism, and more. However, the latter optical properties are only observed in intricate architectures, which are highly demanding in terms of nanofabrication and hence less scalable and far away from device implementation. Here, a series of metasurfaces covering centimeter areas and operating in the visible spectrum are presented, which are produced from the combination of nanoimprinting lithography and oblique angle metal evaporation. The potential of this scalable approach is illustrated by easily fabricating metasurfaces engineered to exhibit artificial optical magnetism, tunable linear polarization dependent response, chirality with g‐factor of 0.2, and photoluminescence enhancement of 20 times over a 9 mm2 area., The Spanish Ministerio de Economía, Industria y Competitividad (MINECO) is gratefully acknowledged for its support through Grant No. MAT2016‐79053‐P and through Grant No. SEV‐2015‐0496 in the framework of the Spanish Severo Ochoa Centre of Excellence program. This project received funding from the European Research Council (ERC) under the European Union's Horizon 2020 research and innovation program (Grant Agreement Nos. 637116, ENLIGHTMENT and 648901, FOREMAT) and the Generalitat de Catalunya program AGAUR 2017‐SGR‐00488. P.M. acknowledges financial support from an FPI contract (2017) of the MICINN (Spain) cofunded by the ESF. L.A.P. is thankful to the Marie Sklodowska‐Curie Actions (H2020‐MSCA‐IF‐2018) for grant agreement No. 839402, PLASMIONICO.