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Minutea??Scale Rapid Crystallization of a Highly Dichroic 2D Hybrid Perovskite Crystal toward Efficient Polarizationa??Sensitive Photodetector
摘要： 2D hybrid perovskites demonstrate better performances than 3D counterparts in certain optoelectronic devices, whereas their natural attributes cannot be extracted from microcrystalline films, such as the natural dichroism for polarized light detection. Herein, for the first time, unusual minute-scale rapid crystallization is developed to grow bulk crystals of 2D hybrid perovskite, (FPEA)2PbI4 (1, FPEA is p-fluorophenethylammonium), which enables superior carrier transport property (≈64.1 ns) and low trap density (≈1010 cm?3). The rapid growth rate of 27.3 mm3 h?1 is almost two orders of magnitude higher than for other 2D counterparts. Strikingly, its natural quantum-confined motif results in extraordinary dichroism with optical absorption ratio αc/αa ≈ 2.05, revealing great promises for polarized light detection. Consequently, crystal-based photodetectors exhibit large photocurrent dichroic ratio Imax/Imin ≈ 2.1, fast response time (400 μs), and high detectivity (1011 Jones) to the polarized light. This is the record-fast crystallization of highly dichroic 2D hybrid perovskites, which opens a new prospect for their future optoelectronic device applications.
关键词： optical dichroism,rapid crystallization,polarized light detectors,hybrid perovskites
更新于2025-09-19 17:13:59
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Surface Polariton‐Like s‐Polarized Waveguide Modes in Switchable Dielectric Thin Films on Polar Crystals
摘要： Surface phonon polaritons (SPhPs) and surface plasmon polaritons (SPPs), evanescent modes supported by media with negative permittivity, are a fundamental building block of nanophotonics. These modes are unmatched in terms of field enhancement and spatial confinement, and dynamical all-optical control can be achieved, e.g., by employing phase-change materials. However, the excitation of surface polaritons in planar structures is intrinsically limited to p-polarization. On the contrary, waveguide modes in high-permittivity films can couple to both p- and s-polarized light, and in thin films, their confinement can become comparable to surface polaritons. Here, it is demonstrated that the s-polarized waveguide mode in a thin Ge3Sb2Te6 (GST) film features a similar dispersion, confinement, and electric field enhancement as the SPhP mode of the silicon carbide (SiC) substrate, while even expanding the allowed frequency range. Moreover, it is experimentally shown that switching the GST film grants nonvolatile control over the SPhP and the waveguide mode dispersions. An analytical model is provided for the description of the GST/SiC waveguide mode and it is shown that the concept is applicable to the broad variety of polar crystals throughout the infrared spectral range. As such, complementarily to the polarization-limited surface polaritons, the s-polarized waveguide mode constitutes a promising additional building block for nanophotonic applications.
关键词： waveguide modes,infrared spectral range,phase-change materials,surface plasmon polaritons,silicon carbide,nanophotonics,Ge3Sb2Te6,surface phonon polaritons,s-polarized light
更新于2025-09-19 17:13:59
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Photoinduced Chirality Switching of Metal-Inorganic Plasmonic Nanostructures
摘要： Chiral plasmonic nanodevices whose handedness can be switched reversibly between right and left by external stimulation have attracted much attention. However, they require delicate DNA nanostructures and/or continuous external stimulation. In this study, those issues are addressed by using metal-inorganic nanostructures and photoinduced reversible redox reactions at the nanostructures, namely site-selective oxidation due to plasmon-induced charge separation (PICS) under circularly polarized visible light (CPL) and reduction by UV-induced TiO2 photocatalysis. We irradiate gold nanorods (AuNRs) supported on TiO2 with right- or left-CPL to generate electric fields with chiral distribution around each AuNR, and to deposit PbO2 at the sites where the electric fields are localized, for fixing the chirality to the AuNR. The nanostructures thus prepared exhibit circular dichroism (CD) based on longitudinal and transverse plasmon modes of the AuNRs. Their chirality given by right-CPL (or left-CPL) is locked until PbO2 is re-reduced under UV light. After unlocking by UV, the chirality can be switched by left-CPL (or right-CPL) irradiation, resulting in reversed CD signals and locking the switch again. The handedness of the chiral plasmonic nanodevice can be switched reversibly and repeatedly.
关键词： plasmon-induced charge separation,circular dichroism,chiral plasmonic nanodevice,nanofabrication,circularly polarized light
更新于2025-09-19 17:13:59
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Soliton propagation of electromagnetic field vectors of polarized light ray traveling in a coiled optical fiber in Minkowski space with Bishop equations
摘要： In this paper, we ?rstly obtain the evolution equations of the magnetic ?eld and electric ?eld vectors of polarized light ray propagating along a coiled optical ?ber in Minkowski space. Then we de?ne new kinds of binormal motions and new kinds of Hasimoto transformations to relate these evolution equations into the nonlinear Schrodinger’s equation. During this procedure, we use a parallel adapted frame or more commonly known as Bishop frame to characterize the coiled optical ?ber geometrically. We also propose perturbed solutions of the nonlinear Schr¨odinger’s evolution equation that governs the propagation of solitons through the electric ?eld (E) and magnetic ?eld (M) vectors. Finally, we provide some numerical simulations to supplement the analytical outcomes.
关键词： polarized light,Minkowski space,nonlinear Schr?dinger’s equation,coiled optical fiber,soliton propagation,Bishop equations
更新于2025-09-16 10:30:52
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Development of a liquid crystal laser using a simple cubic liquid crystalline blue phase platform
摘要： A liquid crystal laser using a polymer-stabilized simple cubic blue phase (BPII) platform has been scarcely reported because the polymer stabilization of a BPII is relatively di?cult compared to that of a body-centered-cubic BP (BPI). In this study, we succeeded in fabricating a dye-doped polymer-stabilized BPII laser with wide operating-temperature ranges over 15 (cid:1)C including room temperature. A narrow and sharp single laser peak with a full width at half maximum of approximately 2 nm was derived from the photonic band edge e?ect of the BPII-distributed feedback optical resonator. As a result, the laser emission was a circularly polarized light, which matched the chirality of the proposed pure BPII.
关键词： liquid crystal laser,circularly polarized light,photonic band edge effect,polymer-stabilized,BPII,simple cubic blue phase
更新于2025-09-16 10:30:52
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Chiral Reduced-Dimensional Perovskite for Efficient Flexible Circularly Polarized Light Photodetector
摘要： Advancements in exploring new chiral perovskites are highly demanded to improve the circular polarized light (CPL) detection efficiency to date. Reduced-dimensional (quasi-2D) perovskites thus emerged as the most promising candidates due to its appealing characteristics. We herein reported new chiral quasi-2D perovskite single crystals (SCs) synthesis, and investigate their CPL detecting capability for the first time. We proved quasi-2D chiral perovskites, [(R)-β-MPA]2MAPb2I7 ((R)-β-MPA = (R)-(+)-β-methylphenethylamine, MA = methylammonium), do possess intrinsic chirality and have the capability to distinguish different polarization states of CPL photons. Corresponding quasi-2D perovskite SCs CPL photodetector exhibit excellent detection performance. In particular, our device responsivity is almost one order of magnitude higher than the best reported 2D perovskite CPL detectors to date. On this basis, we carefully modulate the film’s crystallization dynamics to facilitate its carrier transport. We prove that parallelly oriented perovskite films with homogeneous energy landscape are crucial to maximize the device’s carrier collection efficiency. The obtained responsivity and linear dynamic range (LDR) of this flexible chiral quasi-2D perovskite thin-film photodetector are comparable with the best reported results to date. The photodetector also exhibits superior mechanical flexibility and durability, representing one of the most sensitive and robust CPL photodetector to date.
关键词： circular polarized light,photodetector,reduced-dimensional perovskites,chiral perovskite,crystallization dynamics
更新于2025-09-16 10:30:52
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[IEEE 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Munich, Germany (2019.6.23-2019.6.27)] 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Controlling Light Polarization from Helical Travelling-Wave Nanoantennas
摘要： Light polarization is a key factor of modern photonics. Tailoring surface plasmons (SPs) in anisotropically-shaped metallic nanostructures introduces the prospect of polarization control at small scale [1]. However, the resulting components remain much larger than the wavelength of light. Here, we present a travelling-wave helical plasmonic antenna (TW-HPA) that overcomes this limit [2]. Due to its non-resonant nature, it differs from existing helical plasmonic structures [3-5], thus extending the concept of travelling-wave helical antenna [6] to optics. Our TW-HPA consists of a narrow gold-coated wire wound up in a screw-like shape forming a tiny helix (Fig. 1a). The gold-coated wire sustains a cutoff-free axially symmetric travelling SPs [7], locally excited with the dipolar mode of a rectangular aperture nanoantenna right at the helix's pedestal. In the course of propagation, the plasmon wire mode acquires orbital angular momentum (OAM). Due to the sharp curvatures, the OAM of the SP mode match the spin angular momentum (SAM) of free-space propagating photons [8]. On the basis of this OAM-to-SAM transfer, individual TW-HPA can produce circularly polarized directional light on the subwavelength scale through a swirling-plasmon effect. Such TW-HPAs can then be closely packed to build micron scale arrangements of tiny circularly polarized light sources of desired handedness and tunable intensities, which could open new perspectives in a large panel of photonic applications requiring local addressing, such as detectors, displays, optomagnetic recording as well as quantum information. By optically coupling four TW-HPAs of opposite handedness (Fig.1b), we obtained a phase plate occupying a volume smaller than a cubic wavelength whose polarization properties have never previously been demonstrated. Switching between left and right circular polarizations (LCP and RCP) occurs when the incident linear polarization is rotated by an angle of 52°, instead of 90° as for standard quarter wave plates. Based on the spin-orbit interaction of light, our method is versatile, robust and leads to ultracompact plasmonic polarizers and unconventional phase plates. Taken as individual or coupled structures, TW-PHAs may pave the way towards highly integrated polarization-encoded optics, particularly for the generation and control of spin-encoded photon qubits in quantum information and optical spintronics.
关键词： Light polarization,orbital angular momentum,surface plasmons,circularly polarized light,optical spintronics,quantum information,spin angular momentum,helical travelling-wave nanoantennas
更新于2025-09-11 14:15:04
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[IEEE 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Munich, Germany (2019.6.23-2019.6.27)] 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Comparative Study of Harmonic Generation in Air and Argon in Light Filaments Driven by Circularly Polarized Mid-IR Pulses
摘要： A generation of optical harmonics by circularly polarized light, which is in general forbidden in an isotropic medium, was recently observed in molecular gases where molecules were aligned and oriented by another linearly polarized laser pulse or by pulses with twisted polarization. In order to generate nth-harmonic with circularly polarized light, a molecule has to “absorb” n photons, having the same handedness, and to emit a single nth harmonic photon while fulfilling the energy and the momentum conservation laws, meaning a necessity to excite the molecule to appropriate rotational state. One can do this by means of intrapulse rotational Raman scattering, which prepares the molecule in the excited state through a subsequent absorption of (n-1) same-handed photons. All previously reported experimental studies on circular harmonic generation in molecular gases were performed with visible/near-IR drivers, in either gas jets or in standing cells and with pre-alignment of molecules by an additional laser pulses. Here we report on the studies of self-action of elliptically polarized mid-IR pulses on the generation of low-order harmonics in filaments ignited in air and in argon, representing a molecular and an atomic gas respectively. The harmonics were driven by 20-mJ, sub-100 fs mid-IR pulses, centred at 3.9 μm wavelength. In the experiments filamentation was assisted by focusing light with a spherical mirror of ROC=-2500 mm into an open-end tube, through which Ar gas was flown at slight overpressure. Polarization of the pulses was controlled by a broadband quarter wave plate (QWP). Spectra of 5th and 7th harmonics were recorded after the filaments with a grating spectrometer (HR4000, OceanOptics). Polarization state of the generated harmonics was analysed with a Glan-Taylor polarizer.
关键词： filaments,argon,circularly polarized light,mid-IR pulses,harmonic generation,air
更新于2025-09-11 14:15:04
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Cellulose-Based Microparticles for Magnetically Controlled Optical Modulation and Sensing
摘要： Responsive materials with birefringent optical properties have been exploited for the manipulation of light in several modern electronic devices. While electrical fields are often utilized to achieve optical modulation, magnetic stimuli may offer an enticing complementary approach for controlling and manipulating light remotely. Here, the synthesis and characterization of magnetically responsive birefringent microparticles with unusual magneto-optical properties are reported. These functional microparticles are prepared via a microfluidic emulsification process, in which water-based droplets are generated in a flow-focusing device and stretched into anisotropic shapes before conversion into particles via photopolymerization. Birefringence properties are achieved by aligning cellulose nanocrystals within the microparticles during droplet stretching, whereas magnetic responsiveness results from the addition of superparamagnetic nanoparticles to the initial droplet template. When suspended in a fluid, the microparticles can be controllably manipulated via an external magnetic field to result in unique magneto-optical coupling effects. Using a remotely actuated magnetic field coupled to a polarized optical microscope, these microparticles can be employed to convert magnetic into optical signals or to estimate the viscosity of the suspending fluid through magnetically driven microrheology.
关键词： magneto-optical properties,polarized light,cellulose nanocrystals,microfluidics,microparticles
更新于2025-09-11 14:15:04
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Optically Controlled Orbitronics on a Triangular Lattice
摘要： The propagation of electrons in an orbital multiplet dispersing on a lattice can support anomalous transport phenomena deriving from an orbitally induced Berry curvature. In striking contrast to the related situation in graphene, we find that anomalous transport for an L ? 1 multiplet on the primitive 2D triangular lattice is activated by easily implemented on site and optically tunable potentials. We demonstrate this for dynamics in a Bloch band where point degeneracies carrying opposite winding numbers are generically offset in energy, allowing both an anomalous charge Hall conductance with the sign selected by off-resonance coupling to circularly polarized light and a related anomalous orbital Hall conductance activated by layer buckling.
关键词： Berry curvature,anomalous transport,circularly polarized light,triangular lattice,orbital Hall conductance
更新于2025-09-11 14:15:04