Circularly polarized light detection using chiral hybrid perovskite

Circular polarization detection has important applications in the field of infrared detection. In this paper, a chiral metamaterial microcavity is designed to enhance the recognition of circularly polarized light (CPL) by a quantum well infrared photodetector (QWIP). By sandwiching the quantum well material and GaAs electrodes between a metallic chiral metamaterial and a gold substrate to form a microcavity structure, CPL discrimination can be achieved, and inter-subband absorption in the quantum well active region can also be improved. The electric field distribution is calculated and analyzed with the finite-difference time-domain method. Under the incidence of left circularly polarized light, the metallic chiral metamaterial on the surface excites the surface plasmon polariton (SPP) effect, which enhances the electric field ( E Z ) perpendicular to the growth direction of the quantum well, and the coupling efficiency can reach 950% at 14.9 µm wavelength. The SPP resonance wavelength matches the inherent response wavelength of the quantum well, so the inter-subband absorption of the quantum well is increased to about 0.9. At right circularly polarized light incidence, the coupling efficiency is only 105%, and the inter-subband absorption is only about 0.1 because the SPP effect is not effectively excited. Since chiral metamaterials can enhance the circular dichroism of quantum wells, when our designed structure is combined with QWIP, the circular polarization extinction ratio of QWIP can be increased to nine, which is much higher than 2.5 for a typical circular polarization detector. In addition, the inter-subband absorption will also be greatly improved under the incidence of CPL in a specific rotation direction. By optimizing the structural parameters, the resonance wavelength can be matched with the QWIP of different detection bands, which provides a new idea for the improvement of the performance of a quantum well infrared circular polarization photodetector in the long wave range.

Circularly polarized light (CPL) detection is important in the field of advanced optoelectronics. Traditionally, CPL detection with optical elements is limited by the challenge of integration. Chiral materials have been investigated for direct CPL detection without complex optical elements. However, chiral structures such as the CPL absorption layer need further investigation owing to the low anisotropy factor (gph). Herein, we demonstrate a composite structure combining chiral cellulose nanocrystals (CNCs) and TiO2 nanotube arrays (TNAs) for CPL detection. This CNC–TNA structure is fabricated by evaporation-induced self-assembly of CNCs on the top of electrochemically anodized TNAs. The excellent ability to distinguish between left-handed CPL (LCPL) and right-handed CPL (RCPL) is achieved using CNC–TNAs as photoelectrodes. Benefitting from the chiral nematic phase of CNCs, which selectively reflect LCPL and transmit RCPL, gph of CNC–TNA photoelectrodes reaches 0.33, indicating a highly effective distinguishability to CPL. CNC–TNA photoelectrodes realize the CPL detection with high gph (0.33), fast response (0.8 s), and cycling stability under time-varying CPL illumination. In addition, they can track the phase difference of elliptically polarized light due to the sensitivity to polarization states. The CNC–TNA composite structure opens up a potential approach for CPL detection.

Circularly polarized light detection has attracted growing attention because of its unique application in security surveillance and quantum optics. Here, through designing a chiral polymer as a donor, a high-performance circularly polarized light detector is fabricated, successfully enabling detection from ultraviolet (300nm) to near-infrared (1100nm). The chiroptical detector presents an excellent ability to distinguish right-handed and left-handed circularly polarized light, where dissymmetries in detectivity, responsivity, and electric current are obtained and then optimized. The dissymmetry in electric current can be increased from 0.18 to 0.23 once an external magnetic field is applied. This is a very rare report on the dissymmetry tunability by an external field in chiroptical detectors. Moreover, the chirality-generated orbital angular momentum is one of the key factors determining the performance of the circularly polarized light detection. Overall, the organic chiroptical detector presents excellent stability in detection, which provides great potential for future flexible and compact integrated platforms.

Detection of circularly polarized light (CPL) has a high potential for development of various optical technologies. Conventional photodetectors require optical polarizers on the device to detect polarized light, and this causes substantial losses of sensitivity and resolution in light detection. Here, we report direct CPL detection by a photodiode using a helical one-dimensional (1D) structure of lead halide perovskites composed of naphthylethylamine-based chiral organic cations. The 1D structure with face-sharing (PbI6)4- octahedral chains whose helicity is largely affected by chiral cations shows intense circular dichroism (CD) signals over 3000 mdeg at 395 nm with the highly anisotropy factor (g CD) of 0.04. This high CD enables photocurrent detection with effective discrimination between left-handed and right-handed CPLs. The CPL detector based on this 1D perovskite achieved the highest polarization discrimination ratio of 25.4, which largely surpasses the direct detecting CPL devices (<4) using chiral plasmonic metamaterials and organic materials.

Chiral inorganic semiconductors with high dissymmetric factor are highly desirable, but it is generally difficult to induce chiral structure in inorganic semiconductors because of their structure rigidity and symmetry. In this study, we introduced chiral ZnO film as hard template to transfer chirality to CsPbBr3 film and PbS quantum dots (QDs) for circularly polarized light (CPL) emission and detection, respectively. The prepared CsPbBr3/ZnO thin film exhibited CPL emission at 520 nm and the PbS QDs/ZnO film realized CPL detection at 780 nm, featuring high dissymmetric factor up to around 0.4. The electron transition based mechanism is responsible for chirality transfer.Graphical

Due to their strong optical activity, chiral metamaterials are attractive optical elements for the control of the polarization of light. Efficient broadband circular polarizers can be implemented through chiral nanostructures that are periodic and possess certain spatial symmetries. Here, we demonstrate a new method to fully characterize any generalized chiral medium without the use of optical phase-retarding elements, such as quarter-wave plates. Using the advantage of symmetry considerations, all parameters of the complex Jones matrix associated with the metamaterial were determined by two linear-polarization experiments. A coordinate transformation then enabled the calculation of the gyro-optical response of the sample, i.e., its circular dichroism and circular polarization conversion, which is shown to be in good agreement with direct measurements. This approach is versatile, allowing to calculate the optical response in intensity and phase of any generalized chiral metamaterial upon linear, circular, or elliptical polarized illumination.

Circularly polarized light (CPL) detection is crucial for optical communication, bioimaging and quantum computing. However, CPL detectors based on chiral low-dimensional perovskites face a trade-off between optoelectronic performance and CPL discrimination, and typically exhibit a CPL response within a narrow spectral range. Here, we overcome these limitations by integrating three-dimensional (3D) and chiral-two-dimensional (2D) perovskites. The 3D perovskite serving as the photoabsorption layer extends the detection range to 760 nm and enhances optoelectronic responses, while also generating spin-polarized carriers through large Rashba splitting. The chiral-2D perovskite achieves spin filtering efficiency up to 80%. The synergy between spin polarization and chiral-induced spin selectivity processes enables a panchromatic CPL response, with a photocurrent asymmetry factor exceeding 0.28 across the visible spectrum and peaking at 0.35. Furthermore, our detector achieves a detectivity of 3.7×1011 Jones. Our work introduces a spin manipulation strategy for panchromatic CPL detection, expanding the scope of spintronics applications.

Recently, many researches on Al-doped ZnO (AZO) thin film based transparent conducting oxide (TCO) have been intensively investigated for the electronic and display device applications. In this study, AZO thin films with different thicknesses were deposited on polyethylene terephthalate (PET) substrates by sol-gel spin coating at a relatively low temperature. By optimizing the AZO thickness, maximum figure of merit (FOM) values were investigated and discussed. Commonly, PET substrates are used in the fabrication of flexible display devices. However, because of the low melting temperature of the PET substrate (~200 °C), AZO thin films spin-coated on PET substrates cannot be subjected to crystallization at high temperatures. Therefore, alternative advanced optical annealing method was considered to crystalize the AZO thin films on the PET substrates. In this experiment, optical annealing method will be proposed. To increase electrical conductivity, Platinum (Pt) dots were sprayed on the AZO sample to improve the electric conductivity. The Pt-spotted AZO thin films on flexible PET substrates prepared by sputtering exhibited high electrical conductivities and high optical transmittances. The 0.63 nm-thick Pt/AZO/PET film exhibited a transmittance of 80% in the 380-800 nm range and the 3.78 nm-thick Pt/AZO/PET film exhibited a resistivity of 5.61×10-4 Ώ·m. Notably, the 159 nm-thick Pt/AZO/PET film exhibited an FOM of 156. Moreover, the sheet resistances and transmittances of the prepared AZO/PET films were determined.

We propose ultrathin planar chiral metamaterials (CMs) based on square split rings (SSRs), which can change linearly polarized (LP) electromagnetic (EM) wave to circularly polarized (CP) EM wave at will. The EM resonant properties of the proposed CMs including magnitude, phase, retrieved electromagnetic parameters, and chirality are demonstrated. According to the polarization property of the proposed CMs, a CP patch antenna using the proposed CMs is constructed. Placing the proposed CMs in the presence of a conventional LP patch antenna, the antenna polarization mode can be changed from LP mode to CP mode. The antenna performances are investigated numerically and experimentally. A simple method for realizing CP antenna is provided using the present CMs. It can be expected that the proposed CP antenna can be used in electronic reconnaissance and jamming, mobile communication, and global position system.

Circularly polarized light (CPL) imaging and detection offer powerful capabilities for anti-counterfeiting, quantum communication, and material analysis. However, their practical implementation is hindered by challenges in achieving broadband performance and scalable integration into compact and flexible devices. Chiral multiferroic materials, chirality-controlled magnetoelectrics, are especially promising due to their unique coupling between CPL-guided electric and spin properties. Here, we report chiral semiconducting multiferroics that exhibit distinct chirality-dependent absorption, enabling dual-mode CPL detection via both photocurrent and ferromagnetic resonance signals. Notably, we demonstrate high sensitivity and stability in both contact and noncontact CPL detection and imaging, achieved through photogenerated charge modulation coupled with magnetic switching. Furthermore, we designed and developed a flexible chiral multiferroic detector capable of high-sensitivity CPL mapping. These findings expand multiferroic materials for high-performance CPL sensors and advanced information processing devices.

This p a per presents a review of the chiral metamateri a ls (CMM) a nd their different specific properties like circul a r dichroism , negative refractive index , and giant optic a l activity. The physical properties of metamaterials circul a r dichroism a nd the method of retrieval of effective parameters of the CMM are discussed in detail. The various classes of the chiral metamaterial and their results of the simulation are presented. The study shows that the chiral met a m a terials have the ability to convert linearly pol a rized wave into the circul a rly polarized wave in microw a ve and optical frequency range. Figure of Merit of the chiral metam a terial is rel a tively low comp a red with ordin a ry metam a terials at given resonant frequencies which limit applicable frequency b a nd of neg a tive refr a ctive indices that c a n be subst a ntially improved using a substr a te with lower loss dielectric. The future of chiral metam a terial is a lso briefly discussed. Keywords: Circular dichroism, chir a l met a material, gi a nt optical activity, LCP, negative refractive index, RCP Cite this Article Manoj Kumar, Preet Kaur. A Review on Chiral Metamaterials and its Applications in Antennas . Journal of Microwave Engineering & Technologies . 2018; 5(2): 5–16p.

A circularly polarized (CP) patch antenna with a new chiral metamaterial structure was proposed. The proposed CP antenna is composed of a conventional linearly polarized patch antenna and a chiral metamaterial (CMM) board. For the CMM unit cell, the geometric parameters of the two pieces of copper films that are patterned on opposite sides of an FR-4 board are quite different. The function that a linear-polarization wave is converted into a circular polarization wave can be realized by the designed structure through simulation verification. When the CMM board is placed in the front of a conventional linear-polarized patch antenna, the antenna polarization mode can be changed to the circular polarized mode. The antenna performances have been investigated numerically and experimentally. Meanwhile, the new CMM structure could be applied to the field of circular-polarized antenna.

<p indent="0mm">The detection of circularly polarized light (CPL) is vital in a wide range of applications, such as drug screening, biosensing, imaging and quantum optics. However, traditional CPL detection methods use polarization devices to extract light chirality, which is difficult for system integration and miniaturization. This difficulty leads to the development of novel photodetectors that can directly respond to light chirality. Three main approaches are taken to achieve direct CPL detectors: material chirality, structural chirality and the nontrivial photodetection process, which can transfer spin information into the direction of the photocurrent. Here, we review the mechanisms and recent work of these three categories of direct CPL photodetectors.

Although chiral semiconductors have shown promising progress in direct circularly polarized light (CPL) detection and emission, they still face potential challenges. A chirality-switching mechanism or approach integrating two enantiomers is needed to discriminate the handedness of a given CPL; additionally, a large material volume is required for sufficient chiroptical interaction. These two requirements pose significant obstacles to the simplification and miniaturization of the devices. Here, room-temperature chiral polaritons fulfilling dual-handedness functions and exhibiting a more-than-two-order enhancement of the chiroptical signal are demonstrated, by embedding a 40 nm-thick perovskite film with a 2Dchiroptical effect into a Fabry-Pérot cavity. By mixing chiral perovskites with different crystal structures, a pronounced 2Dchiroptical effect is accomplished in the perovskite film, featured by an inverted chiroptical response for counter-propagating CPL. This inversion behavior matches the photonic handedness switch during CPL circulation in the Fabry-Pérotcavity, thus harvesting giant enhancement of the chiroptical response. Furthermore, affected by the unique quarter-wave-plate effects, the polariton emission achieves a chiral dissymmetry of ±4% (for the emission from the front and the back sides). The room-temperature polaritons with the strong dissymmetric chiroptical interaction shall have implications on a fundamental level and future on-chip applications for biomolecule analysis and quantum computing.

The circular polarizers were mostly made of meta-atom based chiral metamaterials (CMMs). Here we propose an ultra-thin metallic grating based circular polarizer, which can convert any polarization into circular polarization. The circular polarizer consists of two layers: an ultra-thin metallic grating embedded in the substrate and a silicon grating on the substrate surface. The ultra-thin metallic grating, which is thinner than the skin depth and was shown to hold anomalous resonant reflection for transverse magnetic (TM) wave, functions as a quarter-wave plate. We show that the ultra-thin metallic grating based quarter-wave plate can transmit circular polarized wave when the incident linear polarized wave is oriented properly. The silicon grating acts as a linear polarizer which restricts the polarization of the light that reaches the metallic grating. Unlike some of the CMMs, our structure is independent of the incident polarization state. Moreover, the fabrication of our circular polarizer is easier than other double-layer-CMMs, in which the relative position between the two layers must be precisely controlled. Our structure can find its application integrated photonic devices.