Polarization-sensitive Devices Research Articles

Anti-Interference All-Optical Logic Computing Based on a 2D Polarization-Sensitive Photodiode.

Optical logic operation is promising for ultrafast information processing and optical computing due to the high computation speed and low power consumption. However, conventional optical logic devices require either a complex structure and circuit design or a constant voltage supply, which impedes the development of high-density integrated circuits. Here, all-optical logic devices are designed using a self-powered polarization-sensitive photodiode of the GeSe homojunction, which is attributed to an anisotropic band structure and built-in electric field. The single photodiode can realize linear logic functions (AND, OR, NAND) and a nonlinear logic gate (XOR) by programming wavelength, power density, and polarization angle. Moreover, complex logic functions (XNOR, Y = IN1, Y = IN2, Y = IN1, and Y = IN2) can be achieved through integrating two photodiodes in parallel. In addition, the neural network algorithm is utilized to validate the feasibility of all-optical logic computing and anti-interference. This work proposes an avenue to design an all-optical reconfigurable logic operation in polarization-sensitive devices.

Enhanced Optoelectronic Performance and Polarized Sensitivity in WSe2 Nanoscrolls Through Quasi-One-Dimensional Structure.

Transition metal dichalcogenides (TMDs), such as tungsten diselenide (WSe2), are expected to be used in next-generation optoelectronic devices due to their unique properties. In this study, we developed a simple method of using ethanol to scroll monolayer WSe2 nanosheets into nanoscrolls. These nanoscrolls have a quasi-one-dimensional structure, which enhances their electronic and optical properties. The characterization confirmed their unique structure, and the photodetectors made of these nanoscrolls have high sensitivity to polarized light, with anisotropy ratios of 1.3 and 1.7 at wavelengths of 638 nm and 808 nm. The enhanced light response is attributed to the large surface area and quantum wire-like behavior of the nanoscrolls, making them suitable for advanced polarization-sensitive devices.

Complete asymmetric polarization conversion at zero-eigenvalue exceptional points of non-Hermitian metasurfaces.

Non-Hermitian systems can be tuned to exhibit exceptional points, where both eigenvalues and eigenstates coalesce concurrently. The inherent adaptability of photonic non-Hermitian systems in configuring gain and loss has allowed us to observe a plethora of counterintuitive phenomena, largely as a consequence of the eigenspace reduction at these exceptional points. In this work, we propose a non-Hermitian metasurface that, through the incorporation of gain, enables complete asymmetric polarization conversion at an exceptional point with a zero eigenvalue. Specifically, we provide numerical evidence for this concept by designing a non-Hermitian metasurface that facilitates polarization conversion from right to left circular polarization, while preventing conversion in the reverse direction and co-polarized transmission. Furthermore, our investigation reveals that this specific form of complete asymmetric polarization conversion results in maximum circular dichroism in transmission, thereby eliminating the need for external chirality or three-dimensional helical structures. This non-Hermitian technique offers an intriguing approach to designing polarization-sensitive optical devices and systems, further expanding their functionalities and capabilities.

Layer Number and Stacking Engineering of MoS2 Crystals for High-Performance Polarization-Sensitive Photodetector.

The layer and stacking engineering of two-dimensional (2D) transition-metal dichalcogenides (TMDs) gives rise to novel phenomena and multiapplications; thus, TMDs have garnered considerable attention. However, the precisely customized fabrication of stacked 2D materials to date is largely limited to the lack of effective and controllable growth strategies, prone to the unpredictable stacking orders and randomly distributed nucleation sites. Here, we devise an optimized chemical vapor deposition approach for modulating the MoS2 single crystals from monolayer to multilayer with diverse stacking configurations. Significantly, the phototransistor based on monolayer MoS2 single crystal exhibits an ultrasensitive performance with a high photoresponsivity (R) of 3.3 × 104 A W-1 and a remarkable detectivity (D*) of above 1.7 × 1014 Jones at 405 nm light illumination. Ultralow-frequency and angle-resolved polarized Raman spectroscopy is used to systematically uncover the delicate interlayer interactions and crystallographic anisotropy. Moreover, the polarization-sensitive photodetectors using 1-3L MoS2 show a layer number-dependent anisotropic performance, with dichroism ratios of 1.36, 1.44, and 1.52. This work offers a promising method to not only enable the fabrication of new customized layer-, stacking-, and twist-2D materials but also provides the foundation for the development of advanced polarization-sensitive and optoelectronic devices based on stacking transitions.

Tunable polarization-dependent defect modes and lateral shifts of one-dimensional photonic crystals containing Dirac semimetal-based hyperbolic metamaterials and chiral materials

The transmission and lateral shift properties of the one-dimensional photonic crystals containing Dirac semimetal-based hyperbolic metamaterials and chiral material defects are theoretically investigated by using the transfer matrix method in terahertz. It is found that the angle-independent omnidirectional photonic bandgaps (PBGs) for p-polarization can be realized in the photonic crystals made of dielectric and the Dirac semimetal-based hyperbolic metamaterials. However, the PBGs are blue-shifted with the incident angle for s-polarized wave. The omnidirectional PBGs can be tunable with the Fermi energy of the Dirac semimetal, the thickness ratio of the constitute layers and the structural parameters. When one or two isotropic chiral material layers are introduced in the photonic crystals, double or four polarization-dependent defect modes are found in the bandgap under oblique incidence due to the coupling and conversion between different polarized waves in the chiral defects. The frequency interval of the defect modes changes with the chirality parameter and the incident angle. It is also found that when a light is incident on the defective photonic crystals, the giant positive and negative Goos-Hänchen shifts of co-polarization reflected waves can be induced around the defect modes, which are sensitive to the polarization, the incident angle, the incident frequency and the chirality. The special optical properties of the proposed defective multiplayers provide possibilities for practical applications in designing polarization sensitive optical devices, such as filter and sensor.

Giant ab-Plane Birefringence in Quasi-1D Fibrous Red Phosphorus.

Quasi-one-dimensional (quasi-1D) van der Waals crystal fibrous red phosphorus (RP) exhibits pronounced in-plane optical anisotropy, positioning it as a potential candidate for polarization-related micro-nano devices. Unfortunately, a comprehensive investigation into the complex refractive index of fibrous RP and the structure-activity relationship connecting the distinctive quasi-1D structure with optical anisotropy is currently deficient. Herein, we have collectively determined the complex refractive index of the fibrous RP flakes within the ab-plane through Kramers-Kronig (KK) analysis and theoretical calculation. Notably, the maximum birefringence of fibrous RP reaches 0.642@475 nm with an absolute extinction coefficient of only 0.08, superior to the reported traditional optical crystals and the emerging low-dimensional materials as well. The remarkable birefringence can be attributed to the synergistic influence of the large electronic dipole polarizability, anisotropic electron density distribution and the distortion of stereochemically active lone pair (SCALP). This work demonstrates the potential of fibrous RP for polarization-sensitive devices, illuminating possibilities to exploit novel giant birefringent crystals based on the structure-activity relationship.

Ultra-low loss, single polarization hollow-core anti-resonant fiber

In this paper we present a new hollow-core anti-resonant fiber (HC-ARF). The structural asymmetry is constructed by the introduction of elliptical quartz tubes in the core region, which can greatly improve the birefringence and enhance the polarization extinction ratio. Meanwhile, the semicircular and circular nested quartz tubes in the cladding region also contribute to the decrease of the confinement loss of the fundamental mode. A finite element algorithm is used to analyze the effects of each parameter on the performance of the designed HC-ARF. The final simulation results illustrate that the designed structure achieves the values of birefringence and polarization extinction ratio of 2.4×10−5 and 257 in the common wavelength band of 1550 nm, and polarization filtering with a bandwidth of 4 nm. It is worth mentioning that the loss of the y-polarized fundamental mode in the 1550 nm wavelength band reaches an ultra-low value of 0.014 dB/m. The corresponding fundamental mode loss has remained extremely low in the wavelength range considered. Our proposed device still has good bending resistance, where the loss of the y-polarized mode is about 0.04 dB/m and decreases gradually when the bending radius is 5 cm. We believe that the proposed HC-ARF can be used in polarization-sensitive fiber devices and can be widely applied in polarization-sensitive fiber communication systems such as fiber lasers and fiber gyroscopes.

Extraordinary Polarization and Thickness Dependences of Photocarrier Dynamics in PdSe2 Ribbons.

Pentagonal palladium diselenide (PdSe2) stands out for its exceptional optoelectronic properties, including high carrier mobility, tunable bandgap, and anisotropic electronic and optical responses. Herein, we systematically investigate photocarrier dynamics in PdSe2 ribbons using polarization-resolved optical pump-probe spectroscopy. In thin PdSe2 ribbons with a semiconductor phase, the photocarrier dynamics are found to be dominated by intraband hot-carrier cooling, interband recombination, and the exciton effect, showing weak crystalline orientation dependences. Conversely, in thick semimetal-phase PdSe2 ribbons, the photocarrier relaxations governed by the electron-optical/acoustic phonon scattering strongly depend on the sample orientation, albeit with a degradation in in-plane anisotropy following hot-carrier cooling. Furthermore, we analyze the correlations between photocarrier dynamics and anisotropic energy dispersions of electronic structures across a wide range in k space, as well as the contributions from the anisotropic electron-phonon couplings. Our study provides crucial insights for developing polarization-sensitive photoelectronic devices based on PdSe2.

Linear dichroism transition and polarization-sensitive photodetector of quasi-one-dimensional palladium bromide

Perpendicular optical reversal of the linear dichroism transition has promising applications in polarization-sensitive optoelectronic devices. We perform a systematical study on the in-plane optical anisotropy of quasi-one-dimensional PdBr2 by using combined measurements of the angle-resolved polarized Raman spectroscopy (ARPRS) and anisotropic optical absorption spectrum. The analyses of ARPRS data validate the anisotropic Raman properties of the PdBr2 flake. And anisotropic optical absorption spectrum of PdBr2 nanoflake demonstrates distinct optical linear dichroism reversal. Photodetector constructed by PdBr2 nanowire exhibits high responsivity of 747 A⋅W−1 and specific detectivity of 5.8 × 1012 Jones. And the photodetector demonstrates prominent polarization-sensitive photoresponsivity under 405-nm light irradiation with large photocurrent anisotropy ratio of 1.56, which is superior to those of most of previously reported quasi-one-dimensional counterparts. Our study offers fundamental insights into the strong optical anisotropy exhibited by PdBr2, establishing it as a promising candidate for miniaturization and integration trends of polarization-related applications.

Real-time and calibration-free generalized terahertz time-domain spectroscopic ellipsometry

Spectroscopic ellipsometry is a high-precision and powerful optical characterization technique, which can be categorized into two fundamental types of standard and generalized ellipsometry. The latter can obtain the complete Jones matrix to investigate various anisotropic samples. However, terahertz generalized ellipsometry has traditionally relied on frequency-domain instrumentation, which is limited in bandwidth, complicated in polarization manipulation, and slow in operation. In this study, we propose a highly accurate and efficient terahertz time-domain generalized ellipsometer based on a polarization beam coupler-splitter configuration. It measures four independent complex spectra in real-time without mechanical movement, providing ultrahigh data throughput. Each polarizer-antenna unit constructively superimposes their filtering effect, resulting in a 45–65 dB extinction ratio that approaches the system dynamic range. The superb illumination and detection linearity provides an outstanding polarization accuracy and eliminates the need for complicated calibration. Reflection characterization of the magneto-optical properties of an InAs wafer demonstrates the generalized ability to simultaneously obtain multiple dielectric functions. Transmission ellipsometric imaging of liquid crystals subjected to an inhomogeneous electric field further highlights the excellent efficiency. The proposed technique significantly expands the capabilities of terahertz spectroscopy, paving ways to anisotropic materials, in situ monitoring, and polarization-sensitive devices.

Space-confined solid-phase growth of two-domain 1T′-ReSe2 for tunable optoelectronics

Two-dimensional layered ReX2 (X = Se, S) has attracted researcher's great interest due to its unusual in-plane anisotropic optical and electrical properties and great potential in polarization-sensitive optoelectronic devices, while the clean, energy-saving, and ecological synthesis of highly crystalline ReSe2 with controlled domains remains challenging. Here, we develop a space-confined solid-phase approach for growing high-quality two-domain 1T′-ReSe2 with tunable optoelectronic properties by using pure Re powder as a Re precursor. The results show that ReSe2 can be grown at a temperature as low as 550 °C in a small-tube-assisted space-confined reactor, with its size and shape well-tailored via temperature control. A solid-phase two-domain ReSe2 growth mechanism is proposed, as evidenced by combining in situ optical monitoring, ex situ electron microscope, elemental mapping, and polarized optical imaging. Moreover, two-domain ReSe2 transistors are fabricated, which exhibit a switchable transport behavior between n-type and ambipolar character via grain boundary orientation control. This modulation phenomenon is attributed to the different doping levels between grain boundary and single domain. Furthermore, our two-domain ReSe2 photodetectors exhibit a highly gate-tunable current on–off ratio (with a maximum value of ∼8.2 × 103), a polarization-sensitive photo-response, and a high-speed response time (∼300 μs), exceeding most of the previously reported ReX2 photodetectors. Our work, thus, provides a low-consumption, energy-saving growth strategy toward high-quality, domain-controlled ReX2 for highly tunable and high-performance optoelectronics.

Anisotropic carrier dynamics and laser-fabricated luminescent patterns on oriented single-crystal perovskite wafers

Perovskite materials and their applications in optoelectronics have attracted intensive attentions in recent years. However, in-depth understanding about their anisotropic behavior in ultrafast carrier dynamics is still lacking. Here we explore the ultrafast dynamical evolution of photo-excited carriers and photoluminescence based on differently-oriented MAPbBr3 wafers. The distinct in-plane polarization of carrier relaxation dynamics of the (100), (110) and (111) wafers and their out-of-plane anisotropy in a picosecond time scale were found by femtosecond time- and polarization-resolved transient transmission measurements, indicating the relaxation process dominated by optical/acoustic phonon interaction is related to photoinduced transient structure rearrangements. Femtosecond laser two-photon fabricated patterns exhibit three orders of magnitude enhancement of emission due to the formation of tentacle-like microstructures. Such a ultrafast dynamic study carried on differently-oriented crystal wafers is believed to provide a deep insight about the photophysical process of perovskites and to be helpful for developing polarization-sensitive and ultrafast-response optoelectronic devices.

Full-stokes polarization photodetector based on the chiral metasurface with the dislocated double gold rod configurations

The filterless polarization-sensitive optoelectronic device generally has low discrimination, thus severely hindering the development of monolithic full-polarization detectors. We numerically demonstrate a circular polarization photodetector composed of the dislocated 2-bar gold chiral metasurfaces modulating the circular polarization lights and the InGaAs/InP detector chip detecting light intensity signals. The chiral metasurfaces excite the electric field loops with different spins when irradiated with different chiral light, and it explains the high extinction ratios of 21:1 in circularly polarized detectors. In addition, the linear dichroism (LD) and extinction ratios (ER) of the linear polarization device are 0.85 and 80:1, respectively. The excellent ER performance is caused by the boundary state between the metal grating and the InP substrate. The full Stokes pixel based on the six-image-element technique can almost accurately measure arbitrary polarized light at 1550 nm operation wavelength, whose errors of the degree of linear polarizations (Dolp) and the degree of circular polarizations (Docp) are less than −35 dB and −10 dB, respectively.

Perovskite CsCu2I3-based optoelectronic device with exceptional polarization sensitivity via point vacancy modulation

The design of polarization-sensitive, stable self-powered, and broadband photoresponse optoelectronic devices remains a big challenge. Here, the influence of vacancy defects on the electronic structure properties of CsCu2I3 has been studied by density functional theory, which reveals the feasibility of their application in the field of optoelectronic devices, and then, their photogalvanic effects have been investigated based on quantum transport simulations. The results show that the pristine CsCu2I3 and I-vacancy devices indeed generate robust photocurrents under irradiation with linearly polarized light at the near ultraviolet to the visible wavelength without bias, demonstrating the self-powered and broadband response of the devices. The extinction ratios of the pristine CsCu2I3 and I-vacancy devices were 9.84 and 33.02 at zero bias, respectively. In addition, the I-vacancy device exhibits an ultra-high extinction ratio of up to 69.7 at 0.2 V. These results demonstrate potential applications of CsCu2I3-based devices in high performance, low power, and polarization detection.

Polarization-sensitive visible emission of ordered CdSe/CdS nanorod films

The polarization-sensitive optical properties of semiconductor nanorods (NRs) are attractive characteristics for optical devices. Although oriented NR films can provide convenient integration and new application opportunities, the realization of large-area NR films with polarized photoluminescence (PL) remains a challenge. Herein, we fabricated ordered CdSe/CdS NR films on an arbitrary substrate using the Langmuir-Blodgett technology. Polarization-sensitive PL was observed for the NR films. The band-edge exciton fine structure owing to the rod-like morphology and the dielectric effect of the orderly arranged NRs were discussed with a focus on the contribution to polarized photons. The degree of linear polarization of the CdSe/CdS NR films excited a circularly polarized light was approximately 0.30. When linearly polarized ultraviolet (UV) light was used as the excitation source, the PL intensity of the NR films periodically varied with the polarization direction of the UV light. The corresponding PL polarization (i.e., “excitation polarization”) was approximately 0.28. The polarization-sensitive fluorescence (approximately 526 nm) excited by the UV-polarized light (325 nm) demonstrates the potential for realizing low-cost polarization-sensitive devices using only a visible light charge-coupled device system.

Asymmetric Cross-Shaped Optical Antennas with Wide Spectral Tunability and High Optical Cross-Sections

Resonant optical antennas (ROAs) are nanodevices that can enhance the electromagnetic field in their vicinity and scatter the light in the far field. The enhanced field is localized in subdiffraction-limited volume. Their ability to exhibit strong field enhancement in the gap makes them suitable for coupling with quantum emitters. This paper introduced two novel bimodal and triple-modal asymmetric cross-shaped optical nanoantenna designs. The performance of the reported nanoantennas is numerically studied via the finite element method (FEM). The electric field enhancements and optical cross-sections are calculated to characterize the performance of the designs. These nanoantennas are low-symmetry and polarization-sensitive devices. Furthermore, the reported plasmonic nanostructures exhibit two or three tunable resonances in the optical and near-infrared wavelength regions with ultra-high field enhancement. The reported coupled cross-shaped exhibits a field enhancement of 45.9 for the high-energy resonance and 149.4 for the low-energy resonance, respectively, on ETOT/EIN\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\left|{E}_{\\mathrm{TOT}}\\right|/\\left|{E}_{\\mathrm{IN}}\\right|$$\\end{document} scale.

Asymmetric L-shaped resonant optical antennas with plasmon length tuning and high-electric field enhancement

L-shaped resonant optical antennas (ROAs) are low-symmetry plasmonic nanostructures with the unique ability to show two tunable resonances in the optical and near-infrared wavelength regions. The plasmon length of the so-called longitudinal dipolar fundamental plasmon mode of these asymmetric L-shaped ROAs can be used as plasmon resonance building blocks to design polarization-sensitive devices. This paper introduces and numerically analyzes a novel design of asymmetric L-shape ROAs. The reported design offers two resonance modes, i.e., bimodal longitudinal antenna resonance behavior with a high enhancement factor. These two resonances can be selectively excited by changing the linear polarization angle. It is found that the coupled L-shaped ROA with a very small 2 nm gap width exhibits field enhancements 40 and 147.3 on scale left|{E}_{TOT}right|/left|{E}_{IN}right| for the high energy and low energy resonance, respectively. The obtained results and the analysis open a new route for multiple plasmon resonance devices with ultra-high field enhancement that can be easily integrated with future nano-optical circuits with multiple operational frequencies.

Quasi-One-Dimensional ZrS3 Nanoflakes for Broadband and Polarized Photodetection with High Tuning Flexibility.

Two-dimensional (2D) layered materials with low crystal symmetries have exhibited unique anisotropic physical properties. Here, we report systematic studies on the photoresponse of field effect transistors (FETs) fabricated using quasi-one-dimensional ZrS3 nanoflakes. The as-fabricated phototransistors exhibit a broadband photocurrent response from ultraviolet to visible regions, where the responsivity and detectivity can be enhanced via additional gate voltages. Furthermore, benefiting from the strong in-plane anisotropy of ZrS3, we observe a gate-voltage and illumination wavelength-dependent polarized photocurrent response, while its sub-millisecond-time response speed is also polarization-dependent. Our results demonstrate the flexible tunability of photodetectors based on anisotropic layered semiconductors, which substantially broadens the application of low symmetry layered materials in polarization-sensitive optoelectronic devices.

Double resonant tunable second harmonic generation in two-dimensional layered materials through band nesting

We proposed a mechanism to generate giant anisotropic second harmonic nonlinear response via double resonance effect, achieved through band nesting via electronic band-structure engineering. The ideal band setup would be a triplet of nested bands separated by the fundamental resonance energy $\ensuremath{\hbar}\ensuremath{\omega}$. We demonstrate theoretically that the proposed phenomenon can be realized in bilayer SnS by band tuning with perpendicular electrical bias, which maximizes the second harmonic susceptibility by several orders of magnitude. Moreover, the tunability of the polarization anisotropy can be useful for realizing novel polarization-sensitive devices.

Polarization-sensitive photonic bandgaps inhybrid one-dimensional photonic crystals composed of all-dielectric elliptical metamaterials and isotropic dielectrics.

Photonic bandgaps (PBGs) in conventional one-dimensional (1-D) photonic crystals (PhCs) composed of isotropic dielectrics are polarization-insensitive since the optical length within a isotropic dielectric layer is polarization-independent. Herein, we realize polarization-sensitive PBGs in hybrid 1-D PhCs composed of all-dielectric elliptical metamaterials (EMMs) and isotropic dielectrics. Based on the Bragg scattering theory and iso-frequency curve analysis, an analytical model is established to characterize the angle dependence of PBGs under transverse magnetic and transverse electric polarizations. The polarization-dependent property of PBGs can be flexibly controlled by the filling ratio of one of the isotropic dielectrics within all-dielectric EMMs. Assisted by the polarization-sensitive PBGs, high-performance polarization selectivity can be achieved. Our work offers a loss-free platform to achieve polarization-sensitive physical phenomena and optical devices.