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Topological charge (TC) is generally acknowledged as an important attribute of an optical vortex (OV), which indicates the twisted characterization of the wavefront. In most circumstances, the TC remains constant as an integer or fraction along the azimuthal direction. Herein, by transforming the TCs into the trigonometric functions of the azimuthal angle to tailor the spiral phase distributions, we numerically demonstrate generating perfect vortex beams (PVBs) with sine-function TC based on the all-dielectric geometric metasurfaces, whose unit structure is optimized to an ideal half-wave plate. To seek the intrinsic advancements of the proposed PVBs, their orbital angular momentum (OAM) as well as optical gradient force distributions are calculated for diverse particle manipulation. We believe our proposed scheme is desired to provide an original thought for OAM manipulation, information storage, and optical communication.

This publisher’s note contains corrections to a production-related error to Opt. Mater. Express 13, 247 (2023)10.1364/OME.477107.

Topological edge states have an important role in optical modulation with potential applications in wavelength division multiplexers (WDMs). In this paper, 2D photonic crystals (PCs) with different rotation angles are combined to generate topological edge states. We reveal the relationship between the edge states and the rotation parameters of PCs, and further propose a WDM to realize the application of adjustable beams. Our findings successfully reveal the channel selectivity for optical transmission and provide a flexible way to promote the development of topological photonic devices.

Erratum to “Creating perfect composite vortex beams with a single all-dielectric geometric metasurface.” [Opt. Express 30, 40231 (2022)10.1364/OE.475158]. Here are some mistakes in the paper, which needs to be revised.

The diffraction limit of light due to the loss of evanescent waves that carry high spatial frequency information in the far field restricts the practical applications of terahertz imaging technology. In order to break the diffraction limit, we investigate the super-resolution capability of different types of multilayered graphene-dielectric hyperbolic metamaterials. A super-resolution of λ/10 is achieved for both the cylindrical and planar structures. A prominent advantage of graphene-dielectric hyperbolic structures is the dynamic tunability of the dispersion and super-resolution performance by adjusting the chemical potential of graphene through conveniently changing the gate voltage without modifying the geometry of the hyperbolic structures. Furthermore, we have investigated the influence of bilayer thickness variations on the super-resolution performance. Finally, we apply the planar hyperbolic structures for the super-resolution imaging and a roughly five-fold lateral resolution enhancement is realized in our approach. Due to many prominent advantages including super-resolution over broad spectral range, dynamic tunability, good stability and robustness, we believe this work could contribute to the improvement of the resolutions of terahertz imaging systems and the development of hyperbolic metamaterial modulation devices in the terahertz band.

This study proposes a tunable dual-band mid-infrared graphene-based one-dimensional photonic crystal absorber with strong surface phonon polaritons and Tamm phonon polariton coupling. We use an LC circuit, transfer matrices, and coupled harmonic oscillator models to theoretically analyze the different modes, and the theoretical results are consistent with the simulation results. The resonance wavelengths and absorption intensities of the coupled mode can be adjusted by the Fermi level and structure parameters. Moreover, because the perfect dual-band absorption peaks of the designed structure are sensitive to the air layer’s refractive index, we demonstrate the possibility of its application in the field of refractive index sensors and analyze its potential in the field of biomolecular layer sensors. The designed structure also has broad applications in absorbers, photodetectors, and energy harvesting devices due to the excellent performance of the tunable perfect absorption peaks.

Quantum coherence has been considered as a resource for quantum information process in recent years. Sharing the quantum resource distantly is a precondition for quantum communication. In this paper, we explore the quantum coherence properties of the prepared state starting from initially incoherent thermal light source. It is shown that the quantum coherence is directly proportional to the dimension of Hilbert space and therefore employ the orbital angular momentum (OAM) to encode resources. The distribution of biphoton thermal OAM state via the one-sided noisy channel (non-Kolmogorov turbulent atmosphere) is then investigated. It is found that the prepared OAM state can have large amount of quantum coherence, which is maximized when the thermal source is completely incoherent. The turbulence effects on quantum coherence are studied and compared to those on the fidelity and quantum channel capacity. Contrasting to the monotonic decay, the dynamics of coherence displays a peak during the propagation and the mechanism behind is presented. Finally, the dynamics of quantum thermal state can be more robust than that of Bell-like pure state since more interference can be induced. We believe our results is of importance to OAM quantum communication using quantum coherence as a resource.

Halogen perovskites have high refractive indexes and adjustable bandgaps, making them promising materials for all-dielectric and tunable metasurfaces. Herein, we design tunable polarization-converted halogen-perovskite metasurfaces and explained their characteristics in theory by using the Jones matrix. We propose a halogen-perovskite color holographic metasurface with low crosstalk owing to the excellent monochromatic permeability of three halogen perovskites (MAPbCl3: 450 nm; MAPbBr3: 550 nm; MAPbI3: 740 nm). In addition, we build three independent imaging channels to prevent color crosstalk between them to achieve fantastic imaging applications. This study serves as a good reference for research on optical information storage, polarization optics, holographic image encryption.

Because of the low temporal resolution, it is difficult to imaging a moving object using single-pixel imaging. In previous studies, either the frame rate is limited, or the speed and direction is limited to constant. In this work, a fast tracking and imaging method for moving objects is proposed. By using cake-cutting order Hadamard illumination patterns and the TVAL3 algorithm, low-resolution images of each frame are obtained. The displacement is calculated via the cross-correlation between the low-resolution images, and the illumination patterns are modified according to the location results. Finally, a high-quality object image is obtained. This scheme is suitable for moving object imaging with varying speeds and directions. The simulation and experimental results prove that for a 128 × 128 pixels scene, the location and imaging can be realized when 30 samplings are performed for each time interval. We experimentally demonstrate that the proposed method can image a moving object with variational speed with a resolution of 128 × 128 pixels at a frame rate of 150 fps by using a 9 kHz digital micromirror device. The proposed scheme can be used for three-dimensional and long-distance moving object imaging.

In this paper, we propose a high-performance refractive-index sensor at a near-infrared band based on a hybrid Tamm structure. The optical properties of this graphene-based hybrid Tamm plasmonic structure are analyzed and investigated by using the transfer matrix method (TMM). Due to the excitation of the guide mode resonance (GMR) and Tamm plasmon polariton (TPP) resonance, the structure can realize multi-channel perfect absorption. This structure can be utilized as a refractive index sensor because the position of the absorption peak is sensitive to the refractive index of the ambient layer. Therefore, we obtain the sensitivity to 950 nm per refractive index unit (nm/RIU) and figure of merit (FoM) of 161 RIU-1 after studying the performance under different structural parameters. We believe that the proposed configuration is expected to be used to manufacture high-performance biosensors or gas sensor devices and other related applications in the near-infrared band.

Fano resonance is based on a plasmonic metasurface and has many applications in various fields. In this paper, we propose an independently adjustable graphene-based double-layer grating structure. We control multiple Fano resonances at different wavelengths and bandwidths by regulating the Fermi level thanks to the preeminent characteristic of graphene. Here, the equivalent resonator coupled-mode method is used to better describe the Fano resonance of this designed structure adequately, and the transmission spectra fit well. The functional switch could be achieved at different wavelengths by using Fano resonance. We can obtain excellent group refractive index of this designed structure, which means it has superior applications in slow light. The effect of the refractive index of the dielectric layer on the sensing performance is researched so that the structure has a good application in sensors. Furthermore, we look forward to making potential contributions to fabricate integrated optical sensors and devices based on those elaborately designed structures.

In recent years, the research on tunable and high-performance terahertz devices has attracted widespread attention. In this paper, we propose a novel refractive index sensor consisting of monolayer graphene and multilayer photonic crystal with a defect layer. It is found that Tamm plasmon polaritons can be excited at the top graphene interface, which can strongly interact with the defect mode in this coupled structure. The results of numerical simulation demonstrate that the coupling can be either tuned by adjusting the geometric parameters or actively controlled by the chemical potential in graphene as well as the incident angle of light, allowing for tunable dual-band perfect absorption with strong interaction. Moreover, the resonance frequency of the defect mode is sensitive to the changes of the ambient refractive index. The sensitivity and figure of merit of this device as a sensor can reach 1.01 THz per refractive index unit (THz/RIU) and 631.2 R I U − 1 , respectively. In addition to high performance, the sensor does not require phase- or polarization-matching devices, paving the way for the research of optical devices.

We employ non-diffractive Bessel–Gaussian beams to investigate the effect of oceanic turbulence on quantum communication protocols via behaviors of quantum-channel capacity and trace distance, based on the analytical expression of the phase structure function of an orbital-angular-momentum (OAM) beam in underwater wireless optical communication. Our results show that turbulence conditions with a larger inner-scale and outer-scale factors, higher dissipation rate of kinetic energy, lower dissipation rate of the mean-squared temperature, and smaller temperature-salinity contribution ratio are beneficial to quantum communication performance. Moreover, we show that the distribution protocol may be improved by distributing quantum superposition states instead of OAM eigenstates. We believe our work provides the first theoretical exploration of quantum-channel capacity in underwater OAM quantum communication.

Generating a vortex beam is a fundamental task due to the potential applications in wireless communication. Here we propose a kind of high-performance terahertz vortex beam generator with several topological numbers based on the square-split-ring metasurfaces. Via the Fabry–Perot resonance effect of the structure, the transmittance of an orthogonal polarization mode could be remarkably enhanced. We use a Laguerre–Gaussian (LG) mode for illustration and then simulate the far-field propagation of the LG beam by using phase superposition of focusing lens and vortex phase plates. The theoretical and simulation results agree well, which implies a bright application prospect.

In this paper, we study a photonic Bragg waveguide sensor for resonant sensing applications in the THz range. In order to enhance the resolution and detectivity of the sensor, we modify the relatively broad transmission spectrum of the Bragg waveguide with spectrally narrow transmission dips by creating a geometrical defect in Bragg reflector and causing anti-crossing phenomenon between the core-guided mode and defect mode. The spectral position of the resonant dip is highly sensitive to the thickness variation in the vicinity of the waveguide core. By designing and manufacturing a Bragg waveguide which includes several sections with different defect layer thicknesses, we can interrogate more than one sample simultaneously and thereby realize multichannel resonant sensing by directly tracking the independent resonant dips. Furthermore, we demonstrate the waveguide platform for online monitoring of the thickness variation of lactose powders, which is captured on the waveguide core via a centrifugal force using a home-built rotating setup. Additionally, we also demonstrate the waveguide for fingerprint detection of powder analytes, which further enriches the sensing scenario of the sensing platform. Finally, we discuss the advantages and the spectral tailoring flexibility of the THz Bragg waveguides sensors for future implementations.

We study a conductive polymer PEDOT: PSS for infrared thermal detection. We propose to use PEDOT: PSS simultaneously as the thermal sensitive material, infrared absorption layer, thermal insulation layer, as well as the electrical connection material. We demonstrate theoretically and confirm experimentally that PEDOT: PSS has a high temperature coefficient of resistance (TCR) of ∼0.6%/K at room temperature, which is comparable to those inorganic materials commonly used in commercial bolometers. We then experimentally characterize the infrared absorption of a thin PEDOT: PSS film, and we find that it has considerable absorption (over 0.2) in a broad range even with a film as thin as 100nm. This is beneficial to reduce the thermal capacitance and thereby increase the response speed. Finally, we characterize the infrared response of PEDOT: PSS film, and the detectivity is found to be 2×108 cmHz1/2/W. This work is especially inspirational in the design and fabrication of versatile, and highly integrated sensors and detectors, as well as other polymer-based devices and systems.