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Accepted papers to appear in an upcoming issue

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Underwater optical communication performanceunder the influence of the eddy diffusivity ratio

Peng Yue, Mengjie Wu, Yi Xiang, Zongmin Cui, and Xiaohui Luan

Doc ID: 345540 Received 11 Sep 2018; Accepted 11 Nov 2018; Posted 12 Nov 2018  View: PDF

Abstract: Generally, the eddy diffusivity ratio of salinity to temperature is not equal to one,especially in upper and mid-to-high latitude ocean. In this paper, the performance of practicalunderwater optical communication (UOC) systems is investigated by considering the influence ofthe eddy diffusivity ratio other than one. Specifically, using the Rytov theory in weak turbulence,the aperture-averaged scintillation indexes for the plane and spherical waves are derived. Thetypical performance criteria including the mean signal-to-noise ratio (SNR) and bit error rate(BER) are further studied. It is found that the scintillation index and the associated UOCperformance differ between the cases of the unity and variable eddy diffusivity ratio. Suchdifference becomes smaller as the receiving aperture increases.

Effect of Underwater Suspended Particles onthe Transmission Characteristics of PolarizedLaser

Yingluo Zhang, Yingmin Wang, Aiping HUANG, and Xin Hu

Doc ID: 341228 Received 31 Jul 2018; Accepted 09 Nov 2018; Posted 12 Nov 2018  View: PDF

Abstract: The complex problem of the transmission channel of underwater polarized laser iscaused by underwater suspended particles. In order to study the effect of suspended particleson underwater optical communication link and laser polarization characteristics, a methodbased on the combination of Mie scattering theory and Monte Carlo numerical simulation isused to establish the transmission model of underwater photons. This method is applied toanalyse the effect of suspended particle on normalized received energy and channel delay.We also investigate the effects of particle and channel length on the polarizationcharacteristics of four different types of polarized lasers. Theoretical analysis and simulationresults indicate that optical coefficients of particles increase with increasing particle size.Thus, when the transmission channel length is the same, the received normalized energy andlight intensity will decrease, and the channel time delay will increase. Meanwhile, thedepolarization phenomenon of laser will generate with increasing particle size, and particlesize has a greater effect on linearly polarized light than circularly polarized light. Therefore,circularly polarized light maintains good polarization characteristics in underwater laser’stransmission process.

Color induction in equiluminant flashed stimuli

Xim Cerda-Company and Xavier Otazu

Doc ID: 334420 Received 05 Jun 2018; Accepted 06 Nov 2018; Posted 12 Nov 2018  View: PDF

Abstract: Color induction is the influence of the surrounding color (inducer) on the perceived color of a central region.There are two different types of color induction: color contrast (the color of the central region shiftsaway from that of the inducer) and color assimilation (the color shifts towards the color of the inducer).Several studies on these effects used uniform and striped surrounds, reporting color contrast and colorassimilation, respectively. Other authors (Kaneko and Murakami, J Vision, 2012) studied color inductionusing flashed uniform surrounds, reporting that the contrast was higher for shorter flash duration. Extendingtheir study, we present new psychophysical results using both flashed and static (i.e., non-flashed)equiluminant stimuli for both striped and uniform surrounds. Similarly to them, for uniform surroundstimuli we observed color contrast, but we did not obtain the maximum contrast for the shortest (10ms)flashed stimuli, but for 40ms. We only observed this maximum contrast for red, green and lime inducers,while for a purple inducer we obtained an asymptotic profile along flash duration. For striped stimuli,we observed color assimilation only for the static (infinite flash duration) red-green surround inducers(red 1st inducer, green 2nd inducer). For the other inducers’ configurations, we observed color contrastor no induction. Since other studies showed that non-equiluminant striped static stimuli induce colorassimilation, our results also suggest that luminance differences could be a key factor to induce it.

Improving absorption in periodic plasmonic structures through a scattering interface layer

Denis Tihon, S. Withington, Christopher Thomas, and Christophe Craeye

Doc ID: 340048 Received 23 Jul 2018; Accepted 05 Nov 2018; Posted 06 Nov 2018  View: PDF

Abstract: Energy Absorption Interferometry (EAI) is a technique that highlights the independent degrees of freedom through which a structure can absorb energy. These degrees of freedom correspond to the natural absorption modes of the structure. In this paper, we apply this technique to different kinds of plasmonic periodic absorbers to identify the absorption mechanisms that can be exploited for each of them. First, we demonstrate that even for far-field excitations, the plane wave absorption spectrum classically used to assess the efficiency of an absorber is not sufficient to fully characterize it. Then, we show how different absorption mechanisms can be identified through the signature of the absorption modes of the structure. We then exploit them to improve absorption. We show that, exploiting long-range mechanisms, the spatial selectivity of the absorber can be enhanced while using short-range mechanisms, a broad-band increase of the absorption is obtained. Last, we show that simply adding scatterers with the proper periodicity on top of the absorber, the absorption can be increased by more than one order of magnitude.

Different measures of speckle and coherence at theoutput of a multimode optical fiber

Anatoly Efimov

Doc ID: 345299 Received 07 Sep 2018; Accepted 05 Nov 2018; Posted 06 Nov 2018  View: PDF

Abstract: Excitation of a multimode fiber with a focused spatially coherent light of finite bandwidth results in apartially coherent light at the output of the fiber. Here we study the properties of speckle and classicalcoherence of such light with analytical theory, numerical modeling and experimentally. Of particularinterest is the relationship between measures of coherence and speckle and their dependence on inputsource bandwidth and fiber length. Speckle contrast is easy to measure experimentally and there existsat least two different methods to generate ensembles of random speckles. We show that speckle contrastevaluated over the ensemble of external diffusers is related to the number of effective modes—one of thecharacteristics of beam global coherence. The other speckle contrast measure evaluated over the ensembleof random bends and twists of the fiber is related to residual coherence, which is the pedestal on theaverage modulus of the complex degree of coherence function on the output endface of the fiber.

Characterizing the depolarization of circularlypolarized light in turbid scattering media

Callum Macdonald

Doc ID: 336253 Received 28 Jun 2018; Accepted 03 Nov 2018; Posted 05 Nov 2018  View: PDF

Abstract: We investigate the effectiveness of various bulk optical parameters in characterizing the Degree of CircularPolarization (DOCP) of light diffusely reflected from scattering media. It is demonstrated that thetraditional set of bulk optical parameters (namely the scattering and absorption coefficients, and scatteringasymmetry parameter) fail to characterize the observed depolarization. However, we find that thereexists an additional parameter connected to the circular polarization memory phenomenon which consistentlyrelates to observations, even in media with widely varying refractive indices, and particle sizedistributions. This relationship is demonstrated using both Monte Carlo simulations, as well as a newmethod for designing microsphere-based phantom media which contain carefully controlled particle sizedistributions, and depolarization characteristics.

Generalized Interferometry

Mohammad Tavassoly and Hamid Salvdari

Doc ID: 342158 Received 16 Aug 2018; Accepted 02 Nov 2018; Posted 02 Nov 2018  View: PDF

Abstract: When a parallel beam of light undergoes a discontinuous change in phase or in phase gradient in the central part of the beam, two wavefronts with a common border are formed. In this report, we formulate the interference of two such wavefronts and show the conventional diffraction and interference are special cases of a generalized interference with amplitudes that are determined by the distances of observation point from the wavefronts’ boundaries. Also, we modulate a phase function on the interference fringes near the common boundary and show this kind of modulation provides ground for quantitative imaging of phase objects in small scales. Furthermore, we evaluate the theoretical results by relevant experiments and elaborate on features and application potentials of the introduced interferometry.

Minimal smooth lenses for perfect imaging of twowavefronts

Jacob Rubinstein and Katya Shelenkov

Doc ID: 340816 Received 01 Aug 2018; Accepted 29 Oct 2018; Posted 29 Oct 2018  View: PDF

Abstract: The problem of designing a lens for perfectly imaging two incident wavefronts into two respective refractedwavefronts is considered. In particular the problem of deriving a unique such lens of prescribedsmoothness is analyzed. Building upon an idea by Benitez, Minano et al., we propose a method forconstructing such twice-differentiable lenses and derive equations for computing them. The theoreticalconsiderations are supplemented by a few examples.

Imaging with two skew ideal lenses

Jakub Belin and Johannes Courtial

Doc ID: 344455 Received 29 Aug 2018; Accepted 23 Oct 2018; Posted 26 Oct 2018  View: PDF

Abstract: In lens systems, the constituent lenses usually share a common optical axis, or at least a common optical-axis direction, and such combinations of lenses are well understood. However, in recent proposals for lens-based transformation-optics devices [Courtial et al., Opt. Express 26, 17872 (2018)] the lenses do not share an optical-axis direction. To facilitate the understanding of such lens systems, we describe here combinations of two ideal lenses in any arbitrary arrangement as a single ideal lens. This description has the potential to become an important tool in understanding novel optical instruments enabled by skew-lens combinations.

Transmission ofSpatial-Shaped-Diffraction-Resistant-BeamsThrough Stratified Dielectric Media: FiniteEnergy Formulation

João Quaglio Borges and Michel Zamboni-Rached

Doc ID: 336275 Received 26 Jun 2018; Accepted 19 Oct 2018; Posted 19 Oct 2018  View: PDF

Abstract: In this paper, we describe the reflection and transmission of a normally incidentBessel-Gauss beam upon a flat and non-absorbing dielectric interface and use such results todevelop an original method based on Bessel-Gauss beams superposition, capable of providingdiffraction resistant beams whose longitudinal intensity pattern can be modelled on demand evenafter crossing an arbitrary stratified dielectric structure.

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