Polarization Control Research Articles

A Design Study on Polarized Beam Splitter for Visible Light

This study employs the thin film design software TFCale to successfully design and realize a high-efficiency polarization beam splitter suitable for the visible light wavelength range of 400-700 nm, with incident angles between 40 and 50. The design objective was to achieve near 100% reflectance for S-polarized light and near 100% transmittance for P-polarized light. By optimizing the refractive index, thickness, and multilayer structure of the thin film materials, we achieved high-performance optical characteristics. During the design process, we conducted an in-depth investigation of the optical constants of various materials and combined the interference effects of multilayer films to ensure the desired polarization splitting effect within the specified range of incident angles. Simulation results indicate that the film exhibits high-efficiency polarization separation across the entire visible spectrum: the reflectance of S-polarized light remains above 80% within a certain angular range, and the transmittance of P-polarized light also remains above 80%. This high-efficiency polarization beam splitter has broad application prospects in optical instruments, laser systems, display technologies, and other fields requiring precise polarization control. Its superior performance not only enhances the efficiency and accuracy of optical systems but also provides valuable references for future optical thin film design. The study demonstrates that using TFCale for thin film design is an effective method to meet complex optical performance requirements and offers reliable solutions for practical applications

Photonic scheme to generate frequency 24-tupling mm-wave signal using three cascaded polarization modulators without filters

Abstract The paper proposes a new scheme for generating a frequency 24-tupling millimeter-wave (mm-wave) signal using three cascaded polarization modulators (PolMs). In the scheme, three polarization modulators with the cooperation of polarization controller (PC) and polarizer (Pol) in each subsystem are first employed to produce even order optical sidebands. Adjusting the angle of electrical phase shifters (EPS) to eliminate the unwanted even order optical sidebands except (6n)th order optical sidebands. Next, setting the modulation index to 4.968 to eliminate ±6th order sidebands. At last, adjusting the rotation angle of the polarizer placed behind the polarization beam combiner (PBC) to suppress 0th order optical carrier from the upper and lower branches. The obtained pure ±12th order sidebands are fed into the photodiode (PD) beat frequency. After detailed mathematical derivation and simulation verification, the accuracy of the scheme has been verified. The simulation results show that the optical sideband suppression ratio (OSSR) and the radio frequency spurious suppression ratio (RFSSR) can reach 54.49dB and 43.86dB, respectively. Moreover, the impacts of these non-ideal elements on OSSR and RFSSR are analyzed, and an admissible error extent is listed.

Optical Metasurfaces for Biomedical Imaging and Sensing.

Optical metasurfaces, arrays of nanostructures engineered to manipulate light, have emerged as a transformative technology in both research and industry due to their compact design and exceptional light control capabilities. Their strong light-matter interactions enable precise wavefront modulation, polarization control, and significant near-field enhancements. These unique properties have recently driven their application in biomedical fields. In particular, metasurfaces have led to breakthroughs in biomedical imaging technologies, such as achromatic imaging, phase imaging, and extended depth-of-focus imaging. They have also advanced cutting-edge biosensing technologies, featuring high-quality factor resonators and near-field enhancements. As the demand for device miniaturization and system integration increases, metasurfaces are expected to play a pivotal role in the development of next-generation biomedical devices. In this review, we explore the latest advancements in the use of metasurfaces for biomedical applications, with a particular focus on imaging and sensing. Additionally, we discuss future directions aimed at transforming the biomedical field by leveraging the full potential of metasurfaces to provide compact, high-performance solutions for a wide range of applications.

Mechanochemical Synthesis of Phase-Pure CsCu2I3 and Cs3Cu2I5 Phosphors Regulated by Polar Solvents and Their Application in Tunable Chromaticity LEDs.

Lead halide perovskites have garnered interest in light-emitting diode (LED) applications due to their strong emission and tunable properties. However, conventional synthesis methods involve energy-intensive thermal processes and hazardous organic solvents, raising environmental concerns. In this study, we report a simple and eco-friendly mechanochemical approach that produces phase-pure blue-emitting Cs3Cu2I5 (emission at 440 nm) and yellow-emitting CsCu2I3 (emission at 570 nm) phosphors through polarity modulation and control of grinding duration. Our comprehensive analysis of the phase transitions during mechanochemical synthesis reveals that pure Cs3Cu2I5 was synthesized from a 3:2 precursor molar ratio in ethanol for 30 min, while pure CsCu2I3 was obtained from a 1:2 precursor molar ratio in an aqueous solution for 7.5 min. Moreover, Raman spectroscopy, X-ray diffraction, and energy-dispersive X-ray spectroscopy analyses confirmed that phase-pure phosphors were achieved through these methods. Finally, we fabricated a series of color-adjustable LEDs by mixing Cs3Cu2I5 and CsCu2I3 phosphors in different proportions. This demonstrates the potential of our mechanochemical synthesis for the efficient, large-scale production of next-generation lighting materials with tunable emission.

A strategy for fast and precise control of polarity and chirality in magnetic vortices

A strategy for fast and precise control of polarity and chirality in magnetic vortices

Dual–resonance enhancement and polarization control of upconversion luminescence of NaYF4:Yb,Er nanoparticles on 2D metal gratings

In this work, we report enhancement and polarization control of multi–color (green/red) upconversion luminescence (UCL) of lanthanide–doped (NaYF4:Yb,Er) nanoparticles by dual–resonance modes of surface plasmons (SP) on two–dimensional (2D) metal gratings in orthogonal directions. Investigations are performed for the SP resonance modes to be tuned, by adjusting the grating periods, to match any one or two of the green–UCL, red–UCL and excitation wavelengths. It is shown that, for the upconversion nanoparticles (UCNPs) on the 2D gratings with both of the dual resonance modes matching the green–/red–UCL or excitation wavelength, enhancements of the UCLs are roughly doubled, compared with their one–dimensional (1D) counterparts. And when the dual resonance modes match the green– or red–UCL and the excitation wavelength, enhancements of the UCLs are further greatly improved, in spite that the resonance modes for the excitation and emission light are in orthogonal directions. As the emitted UCL photons are largely coupled with the dual SP resonance modes, the radiated green– and red–UCL light can be distinguished by their linear polarization states in orthogonal directions. It is also indicated that polarization of the excitation light can influence the polarization of the UCL light when coupled with the SP resonance modes.

Ultranarrow-linewidth stimulated Brillouin scattering with fundamental acoustic waves

Stimulated Brillouin scattering is a well-known nonlinear optical interaction valued for applications including narrow-linewidth lasers, phase conjugation, sensing, and RF-signal processing such as delay lines and filters. While interaction strength and linewidth directly affect device performance, most strongly interacting Brillouin systems have linewidths of many MHz, limited by the high frequency of the participating acoustic waves. By engineering Forward Inter-Modal Brillouin interactions to access the Fundamental Acoustic Modes (FIM-FAM), strong Brillouin coupling can be extended over a wide frequency range, including lower frequencies that support significantly narrower linewidths. In this work, sub-MHz Brillouin linewidths as narrow as 110 kHz are observed in tapered optical fibers with homogeneous waists. Tight confinement of both the optical and acoustic waves yields Brillouin gains over a thousand times higher than traditional backward Brillouin scattering in standard fibers, and a long waist and low-loss transitions enable a Brillouin interaction strength nearly a hundred times greater than prior taper-based FIM-FAM demonstrations. A specific radius and comprehensive polarization control suppress background scattering by over 40 dB relative to the signal. A comprehensive theoretical model is developed accounting for the dynamical behavior of optical and acoustic waves, reproducing qualitative behavior for several experimental configurations. In addition, the dependence of homogeneity of the linewidth is investigated and reveals a route toward further linewidth reduction by controlling phase-matched frequency variations throughout the waist. Extending strongly coupled Brillouin interactions to ultranarrow linewidths with a recipe for fabrication, detailed characterization techniques, and a comprehensive theoretical treatment will benefit high-performance Brillouin-based photonic applications.

Terahertz‐Wave Polarization Space‐Division Multiplexing Meta‐Devices based on Spin‐Decoupled Phase Control

AbstractThis study presents a generalized design strategy for novel terahertz‐wave polarization space‐division multiplexing meta‐devices, functioning as multi‐polarization generators, modulators, and analyzers. It introduces the spin‐decoupled phase control method by combining gradient phase design with circular polarization multiplexing techniques, enabling exceptional flexibility in controlling the polarization directions and spatial distributions of multiple output beams. The meta‐device M‐4D is significantly demonstrated as proof of concept, which converts an incident linearly polarized wave into four beams with distinct polarization angles. Additionally, the advanced meta‐devices M‐2B and M‐4B are designed to generate two‐vector and four‐vector Bessel beams with tunable spatial polarization distributions. These meta‐devices demonstrate dynamic multi‐polarization beam modulation, validated through simulations and experiments. The proposed method significantly expands the design methodology for multi‐beam polarization control using all‐dielectric metasurfaces and holds promising potential for applications in imaging, sensing, particle manipulation, communication, and information processing. Moreover, it holds potential for adaptation to other spectral ranges.

COMPOSITE LEFT-RIGHT HAND META SURFACE IRS FOR MODERN APPLICATIONS

A meta surface (MTS) is a 2D planner structure of an array of two dimensions. MTS structure is composed from a unit cell structure that is periodically configured to form a surface. A Composite Left-Right Hand (CLRH) Meta surface Intelligent Reflecting Surface (IRS) represents a cutting-edge approach in modern communication and sensing technologies. By integrating left-handed and right-handed materials within a meta surface, this hybrid structure leverages the unique electromagnetic properties of both to enhance signal manipulation and control. The IRS technology is pivotal in applications such as wireless communication, where it can dynamically adjust the propagation environment to optimize signal quality and reduce interference. The composite design offers enhanced bandwidth, polarization control, and tunability, making it ideal for next-generation wireless networks, radar systems, and other advanced electromagnetic applications. The integration of CLRH meta surfaces into IRS platforms presents a significant advancement in the development of reconfigurable and adaptive electromagnetic environments, essential for the growing demands of 5G/6G communication systems and beyond.

A high-temperature multiferroic Tb2(MoO4)3

Magnetoelectric mutual control in multiferroics, which is the electric control of magnetization, or reciprocally the magnetic control of polarization has attracted much attention because of its possible applications to spintronic devices, multi-bit memories, and so on. While the required working temperature for the practical application is much higher than room temperature, which ensures stable functionality at room temperature, the reported working temperatures were at most around room temperature. Here, we demonstrated magnetic control of ferroelectric polarization at 432 K in ferroelectric and ferroelastic Tb2(MoO4)3, in which the polarity of ferroelectric polarization is coupled to the orthorhombic strain below the transition temperature 432 K. The paramagnetic but strongly magnetoelastic Tb3+ magnetic moments enable the magnetic control of ferroelectric and ferroelastic domains; the ferroelectric polarization is controlled depending on whether the magnetic field is applied along [110] or [11¯0]. This result may pave a new avenue for designing high-temperature multiferroics.

High efficient bi-functional metasurface with linear polarization conversion and asymmetric transmission for terahertz region

Abstract Polarization control is crucial in contemporary photonics, but achieving broad bandwidths and high efficiencies remains a significant challenge. Here, we propose a wideband and high-efficiency metasurface designed for linear polarization conversion and asymmetric transmission (AT) in the terahertz region based on a three-layered chiral structure. By integrating a double-split ring resonator with a strip resonator, the proposed design can improve bandwidth and efficiency cross-polarization conversion and AT capabilities for a linearly polarized wave. The operating band for AT is 0.73–3.01 THz with an efficiency above 0.8, while the polarization conversion ratio exceeds 0.99 across the 0.56–3.94 THz range. The underlying physical mechanism behind wideband transmission polarization conversion is fully elucidated through theoretical analysis and the characterization of surface current distribution. The designed structure can be used in terahertz imaging, sensing, and communication.

Low-noise tunable high-repetition-frequency fiber laser based on an active–passive hybrid mode-locking mechanism

A hybrid mode-locked fiber laser that effectively combines the nonlinear polarization rotation (NPR) effect and active mode locking is designed and constructed. In the experiments, mode-locked pulse trains of first to 64th order with selectable harmonic mode locking, corresponding to repetition rates from 16.09 MHz to 1.029 GHz, were realized, and a signal-to-noise ratio of up to 69.45 dB at 1.029 GHz proved the excellent stability of the laser output. The birefringence filter, consisting of a bias-preserving pigtail at the input of the modulator and a polarization controller, allows the laser to achieve a multi-wavelength output of up to eight channels. The inclusion of an NPR structure in the cavity effectively improves the SNR of the actively mode-locked harmonic pulses compared to a single-mechanism mode-locked laser. The laser provides a stable light source for the development of practical optical frequency combs.

Wavelength-Switchable Ytterbium-Doped Fiber Laser Based on All-Fiber Lyot Interferometer Filter

A wavelength-switchable ring-cavity ytterbium-doped fiber laser utilizing an all-fiber Lyot interferometer filter was proposed and experimentally demonstrated. Firstly, the Lyot filter was constructed using a polarization-maintaining fiber (PMF) to obtain a comb interferometer effect, and the free spectrum ranges corresponding to 2.5 and 1 m PMF were 2.2 and 6.4 nm, respectively. Then, wavelength-switchable ytterbium-doped fiber emission was realized in the experiment, and the tunable range for the single-wavelength laser was from 1073.76 to 1086.78 nm, with a power variation of less than 1.959 dB. During the experiment, four different sets of double-wavelength lasers were achieved by adjusting the polarization controller (PC) from 1071.64 to 1081.65 nm; in addition, three different sets of triple-wavelength lasers were realized, and the signal-to-noise ratio (SNR) was more than 33.031 dB. For stable single-, double-, and triple-wavelength lasers, the power shifts were less than 0.574, 0.631, and 1.195 dB, respectively. Through adjusting the PC, quadruple-wavelength-switchable lasers could be realized with an SNR exceeding 26.233 dB.

Power output optimization in complex laser systems by means of polarization control

Abstract Recently, a polarimetric method for thermally-induced polarization change-driven power loss (TIPCL) mitigation in complex laser systems has been developed. However, the final optimization relies on a four-parameter numerical process. This article provides a fully analytical direct calculation alternative to this optimization process. The validity of this approach is demonstrated in previously published data from the pulsed laser system Bivoj/DiPOLE100. The new approach provides a deeper insight into the polarimetric method for TIPCL suppression and also brings a more precise, reliable, and faster alternative to the numerical process used earlier.

Control of valley polarization based on quantum path interference

Control of valley polarization based on quantum path interference

Control of current polarity in concentric metal–insulator-semiconductor tunnel diode (MISTD) structures by designed coupling rings

Control of current polarity in concentric metal–insulator-semiconductor tunnel diode (MISTD) structures by designed coupling rings

Controlled Charge Polarity in WSe2 Field‐Effect Transistor Grown by Self‐Flux Method

In 2D materials, tungsten diselenide (WSe2) has great potential for optical and electronic devices. However, the quality of WSe2 crystals, determined by defects and grain boundaries, currently restricts its performance in controlling carrier‐transport properties. Consequently, the most significant issue achieves superior growth of WSe2 crystals and appropriate metal contacts. Herein, a doping‐free approach to manipulate the polarity of WSe2 transistors by utilizing distinct metal contacts is presented. WSe2 field‐effect transistors are examined employing low‐ and high‐work function metals. In these findings, a transition in polarity from n‐type for In and Cr to p‐type for Pd and Au is demonstrated, showcasing remarkably high on/off ratios (≈107) and mobilities (≈117 cm2 V−1 s−1) at room temperature. This straightforward polarity control technique can be further extended by utilizing contact architecture‐based research in other 2D materials for future nano‐electrical and optoelectronic devices.

Design and analysis of a fabricated modified elliptical patch antenna with slots and partial ground plane techniques for UWB applications

This study presents a novel elliptical microstrip antenna (EMSA) design method for enhanced bandwidth. The proposed EMSA offers versatile polarization control, generating both linear and circular polarization. Wider impedance bandwidths compared to some other patch antennas make it suitable for broadband communication. Its compact size facilitates integration into space-constrained devices. Additionally, it provides polarization diversity for MIMO systems, reducing signal fading. The fabricated EMSA, operating at 7.05 GHz, achieves a simulated bandwidth of 5.7% and a measured bandwidth of 4.28%. It exhibits a return loss of -42 dB, 50 Ω impedance matching, 8.57 dB radiation gain, and a VSWR of 1.016. Two bandwidth enhancement techniques were investigated: reducing the ground plane size and incorporating slots within the patch. The partial ground plane achieved simulated and measured bandwidth improvements of 146% and 167%, respectively. The slotted patch yielded 160% and 180% improvements, respectively.

Metasurface polarization optics: From classical to quantum

Metasurface polarization optics, manipulating polarization using metasurfaces composed of subwavelength anisotropic nanostructure array, has enabled a lot of innovative integrated strategies for versatile and on-demand polarization generation, modulation, and detection. Compared with conventional bulky optical elements for polarization control, metasurface polarization optics provides a feasible platform in a subwavelength scale to build ultra-compact and multifunctional polarization devices, greatly shrinking the size of the whole polarized optical system and network. Here, we review the recent progresses of metasurface polarization optics in both classical and quantum regimes, including uniform and spatially varying polarization-manipulating devices. Basic polarization optical elements such as meta-waveplate, meta-polarizer, and resonant meta-devices with polarization singularities provide compact means to generate and modulate uniform polarization beams. Spatial-varying polarization manipulation by employing the pixelation feature of metasurfaces, leading to advanced diffraction and imaging functionalities, such as vectorial holography, classic and quantum polarization imaging, quantum polarization entanglement, quantum interference, and modulation. Substituting conventional polarization optics, metasurface approaches pave the way for on-chip classic or quantum information processing, flourishing advanced applications in displaying, communication, imaging, and computing.

A dual-band reflective polarizer based meta-surface with higher angular stability for C and X-band applications

A reflective dual-band linear-to-circular polarizer for C and X-band application is presented. The proposed elliptical Frequency Selective Surface (FSS) is capable of enhancing the polarization control and minimizes the cross-polarization compared to traditional circular or square geometries. The linear-to-circular polarization is achieved through two elliptical apertures, where each shape generates orthogonal modes with a 90° phase shift. The inner element targets higher frequencies while the outer element handles lower frequencies, enabling efficient polarization conversion across both bands. The proposed unit cell comprises 14 mm × 14 mm and is fabricated on Rogers RT5880 substrate. It exhibits a reflective polarizer at a center frequency of 7.70 GHz with a bandwidth of (7.64–7.76 GHz) and other at 9.42 GHz with a bandwidth of (9.27–9.57 GHz), respectively. In the proposed FSS, the 7.70 GHz exhibits LH-CP, and RH-CP conversion is provided at 9.42 GHz. In addition, an axial ratio of the FSS of (< 3 dB) demonstrated a circular polarization with a polarization conversion ratio (PCR) of 99.9%. In addition, an equivalent circuit model (ECM) of a reflective polarizer has been verified. Furthermore, angular stability of the FSS can be achieved at various incident angles at 0°, 30°, 60°, and 90°. The polarization conversion operates in frequency bands of C-/X, suitable for wireless systems, radar systems, electromagnetic shielding, and satellite communications.