Notes

Impact in the bodily features of various mental faculties locations for the spatial localization involving fibers photometry indicators.
Displacement measuring interferometry is a crucial component in metrology applications. In this paper, we propose a fiber-based two-wavelength heterodyne interferometer as a compact and highly sensitive displacement sensor that can be used in inertial sensing applications. In the proposed design, two individual heterodyne interferometers are constructed using two different wavelengths, 1064 nm and 1055 nm; one of which measures the target displacement and the other monitors the common-mode noise in the fiber system. A narrow-bandwidth spectral filter separates the beam paths of the two interferometers, which are highly common and provide a high rejection ratio to the environmental noise. The preliminary test shows a sensitivity floor of 7.5pm/Hz at 1 Hz when tested in an enclosed chamber. We also investigated the effects of periodic errors due to imperfect spectral separation on the displacement measurement and propose algorithms to mitigate these effects.Evaporated charge extraction layers from organic molecular materials are vital in perovskite-based solar cells. For opto-electronic device optimization their complex refractive indices must be known for the visible and near infrared wavelength regime; however, accurate determination from thin organic films below 50 nm can be challenging. By combining spectrophotometry, variable angle spectroscopic ellipsometry, and X-ray reflectivity with an algorithm that simultaneously fits all available spectra, the complex refractive index of evaporated Spiro-TTB and C60 layers is determined with high accuracy. Based on that, an optical losses analysis for perovskite silicon solar cells shows that 15 nm of Spiro-TTB in the front of a n-i-p device reduces current by only 0.1 mA/cm2, compared to a substantial loss of 0.5 mA/cm2 due to 15 nm of C60 in a p-i-n device. Optical device simulation predicts high optical generation current densities of 19.7 and 20.1 mA/cm2 for the fully-textured, module-integrated p-i-n and n-i-p devices, respectively.A fast response electrically controlled liquid crystal (LC) lens array is revealed. In order to realize the fast response, a double LC layer structure is adopted. The fabricated LC lens array has a small pitch of 310µm and LC layer with a thickness of 50μm. Experimental results show that the focal length of the LC lens array can be continuously adjusted by low driving voltage (∼6.5Vrms), and the shortest focal length is 0.5mm. The switching between 2D display and 3D display is realized by controlling the voltage off and on state of the LC lens array. Experimental result shows that the 2D/3D switchable display has a fast response time of 16ms. The short pitch LC lens array is expected to be used in high-resolution 2D/3D switchable display.We combine single-pixel imaging and homodyne detection to perform full object recovery (phase and amplitude). Our method does not require any prior information about the object or the illuminating fields. As a demonstration, we reconstruct the optical properties of several semi-transparent objects and find that the reconstructed complex transmission has a phase precision of 0.02 radians and a relative amplitude precision of 0.01.Standard imaging systems are designed for 2D representation of objects, while information about the third dimension remains implicit, as imaging-based distance estimation is a difficult challenge. Existing long-range distance estimation technologies mostly rely on active emission of signal, which as a subsystem, constitutes a significant portion of the complexity, size and cost of the active-ranging apparatus. Despite the appeal of alleviating the requirement for signal-emission, passive distance estimation methods are essentially nonexistent for ranges greater than a few hundreds of meters. Here, we present monocular long-range, telescope-based passive ranging, realized by integration of point-spread-function engineering into a telescope, extending the scale of point-spread-function engineering-based ranging to distances where it has never been tested before. We provide experimental demonstrations of the optical system in a variety of challenging imaging scenarios, including adversarial weather conditions, dynamic targets and scenes of diversified textures, at distances extending beyond 1.7 km. We conclude with brief quantification of the effect of atmospheric turbulence on estimation precision, which becomes a significant error source in long-range optical imaging.Particular waveguide structures and refractive index distribution can lead to specified degeneracy of eigenmodes. To obtain an accurate understanding of this phenomenon, we propose a simple yet effective approach, i.e., generalized eigenvalue approach based on Maxwell's equations, for the analysis of waveguide mode symmetry. In this method, Maxwell's equations are reformulated into generalized eigenvalue problems. The waveguide eigenmodes are completely determined by the generalized eigenvalue problem given by two matrices (M, N), where M is 6 × 6 waveguide Hamiltonian and N is a constant singular matrix. Close examination shows that N usually commute with the corresponding matrix of a certain symmetry operation, thus the waveguide eigenmode symmetry is essentially determined by M, in contrast to the tedious and complex procedure given in the previous work [Opt. Express25, 29822 (2017)10.1364/OE.25.029822]. Based on this new approach, we discuss several symmetry operations and the corresponding symmetries including chiral, parity-time reversal, rotation symmetry, wherein the constraints of symmetry requirements on material parameters are derived in a much simpler way. In several waveguides with balanced gain and loss, anisotropy, and geometrical symmetry, the analysis of waveguide mode symmetry based on our simple yet effective approach is consistent with previous results, and shows perfect agreement with full-wave simulations.We propose a simple method, using the first singular value (FSV) of the spatial correlation of biphotons, to characterize topological phase transitions (TPTs) in one-dimensional (1D) topological photonic waveguide arrays (PWAs). After analyzing the spatial correlation of biphotons using the singular value decomposition, we found that the FSV of the spatial correlation of biphotons in real space can characterize TPTs and distinguish between the topological trivial and nontrivial phases in PWAs based on the Su-Schrieffer-Heeger model. The analytical simulation results were demonstrated by applying the coupled-mode theory to biphotons and were found to be in good agreement with those of the numerical simulation. Moreover, the numerical simulation of the FSV (of the spatial correlation of biphotons) successfully characterized the TPT in a PWA based on the Aubry-André-Harper and Rice-Mele models, demonstrating the universality of this method for 1D topological PWAs. Our method provides biphotons with the possibility of acquiring information regarding TPTs directly from the spatial correlation in real space, and their potential applications in quantum topological photonics and topological quantum computing as quantum simulators and information carriers.In this study, a one-dimensional (1D) two-material period ring optical waveguide network (TMPROWN) was designed, and its optical properties were investigated. The key characteristics observed in the 1D TMPROWN include the following (1) Bound states in continuum (BICs) can be generated in the optical waveguide network. (2) In contrast to the BICs previously reported in optical structures, the range of the BICs generated by the 1D TMPROWN is not only larger, but also continuous. This feature makes it possible for us to further study the electromagnetic wave characteristics in the range of the BICs. In addition, we analyzed the physical mechanisms of the BICs generated in the 1D TMPROWN. The 1D TMPROWN is simple in structure, demonstrates flexibility with respect to adjusting the frequency band of the BICs, and offers easy measurement of the amplitude and phase of electromagnetic waves. Hence, further research on high-power super luminescent diodes, optical switches, efficient photonic energy storage, and other optical devices based on the 1D TMPROWN designed in this study is likely to have implications in a broad range of applications.Deep neural networks have contributed to the progress of image-based wavefront sensing adaptive optics (AO) with the non-iterative regression of aberration. selleck However, algorithms relying on the one-shot point spread function (PSF) typically yield less accuracy. Thus, this paper proposes an iterative closed-loop framework for wavefront aberration estimation outperforming the non-iterative baseline methods with the same computation. Specifically, we simulate the defocus PSF concerning the estimation of the Zernike coefficients and input it into the backbone network with the ground-truth defocus PSF. The difference between the ground-truth and estimated Zernike coefficients is used as a new label for training the model. The prediction updates the estimation, and the accuracy refined through iterations. The experimental results demonstrate that the iterative framework improves the accuracy of the existing networks. Furthermore, we challenge our scheme with the multi-shot phase diversity method trained with baseline networks, highlighting that the framework improves the one-shot accuracy to the multi-shot level without noise.By numerically solving the time-dependent Schrödinger equation and semiconductor Bloch equations, the light-induced residual current in monolayer graphene driven by a circularly polarized few-cycle laser is investigated. An evident current direction reversal is disclosed when the amplitude of the driving electric field exceeds a certain threshold value, which is absent in recent investigation [Nature550, 224 (2017)10.1038/nature23900]. Here the internal physical mechanism for the current reversal is inter-optical-cycle interference under a suitable long laser wavelength. Moreover, the reversal-related laser field amplitude depends sensitively on the ratio of ponderomotive energy to photon energy.Plasmonic nanostructures are good candidates for refractive index sensing applications through the surface plasmon resonance due to their strong dependence on the surrounding dielectric media. However, typically low quality-factor limits their application in sensing devices. To improve the quality-factor, we have experimentally and theoretically investigated two-dimensional gold nanoparticle gratings situated on top of a waveguide. The coupling between the localized surface plasmon and waveguide modes results in Fano-type resonances, with high quality-factors, very similar to plasmonic surface lattice resonances. By combining plasmonic surface lattice resonance and waveguide theory, we present a theoretical framework describing the structures. By immersing the fabricated samples in three different media we find a sensitivity of ∼50 nm/RIU and figure of merit of 8.9, and demonstrate good agreement with the theory presented. Further analysis show that the sensitivity is very dependent on the waveguide parameters, grating constant and the dielectric environment, and by tuning these parameters we obtain a theoretical sensitivity of 887 nm/RIU.
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