Advanced Optical Materials最新文献

Multifunctional optical materials with temperature sensing and anti-counterfeiting properties play an essential role in the commercial applications. Herein, Mn²⁺/Nd³⁺ co-doped Cs₂AgInCl₆ (CAIC) lead-free double perovskites (DPs) is synthesized through a hydrothermal method, which exhibits visible to near-infrared (NIR) luminescence and reversible photochromic properties from yellowish to dark purple. The mechanism investigations on the photoluminescence and photochromic phenomena reveal that the incorporation of Mn²⁺ ions not only acts as an intermediary in the energy transfer process from the host exciton to Nd³⁺ ions, but also plays a pivotal role in the reversible photochromic response. The temperature-dependent luminescence, attributed to the contrasting thermal responses of Mn²⁺ and Nd³⁺ ions, enables precise temperature sensing via the fluorescence intensity ratio method. In addition, the integration of visible red emission, NIR luminescence, and photochromic properties in a single CAIC: Mn²⁺/Nd³⁺ DPs, offers a multilevel anti-counterfeiting strategy. The multifunctional CAIC: Mn²⁺/Nd³⁺ DPs would open up new avenues for advanced optical applications, particularly in the realms of temperature sensing and security anti-counterfeiting.

Metasurfaces are artificially intelligent planar optical devices that can realize excellent functions by optimizing the design of nanostructures and arrays. Metasurfaces have become the preferred approach for fabricating integrated and compact optical systems with micro- and nano-scale solutions for realizing multi-dimensional modulated optical devices. Herein, the realization of multi-fold phase holography is demonstrated by combining switchable optical frequencies with hybrid circular and linear polarization states. The original holographic phase distribution can be inversely optimized using an adaptive momentum gradient descent algorithm. Furthermore, completely different images can be reconstructed when the phase values are several times the original values. The multi-fold phase modulation can be achieved by optimizing the structural distribution of the dielectric metasurface with the incident changeable light frequency and decoupled circular and linear polarization. Different polarization combinations enhance the flexibility of multiple holographic modulations. This technology provides new solutions for dynamic multi-fold beam directional refraction and excitation, orbital angular momentum communication, multi-fold holographic displays, optical encryption and camouflage, light switching, and shaping.

Blue is one of the three primary colors, and it is a crucial element in the regulation and application of organic room-temperature phosphorescence (ORTP). However, the considerable Stokes shift of small organic molecules presents a challenge for creating blue afterglow materials. To address this, host-guest-doped materials are prepared by selecting compounds with similar structures for self-doping. This method effectively regulated blue organic long-lasting phosphorescence. Additionally, the persistent-RTP and organic long-persistent luminescence (LPL) properties can be further enhanced by incorporating a rigid or flexible polymer network, creating a dense environment between the host and guest. Remarkably, the phosphorescence lifetime and afterglow duration of polymer-assisted doped materials are ≈5 times greater than those of host-guest doped crystal materials. Apart from its high efficiency, environmental friendliness, and easy synthesis, this blue ORTP material boasts high thermal stability and flexibility. Furthermore, this blue material demonstrates considerable potential in applications such as information encryption and anti-counterfeiting across various media, including paper, cotton thread, and leaves.

Hyperbolic metasurfaces (HMSs) are artificially-engineered interfaces, exhibiting high anisotropy manifested as hyperbolic dispersion. Their ability to support extremely large momenta with negative diffraction and refraction places them as promising platforms for on-chip super-resolution and enhanced light-matter interaction. While the hyperbolic nature of these structures is experimentally demonstrated, only a limited number of studies have concentrated on their super-resolution capabilities, which are never obtained at visible-frequency for fully harnessing their immense resolution potential. Here, a near-field investigation of visible-frequency HMSs is presented, exploiting their super-resolution capabilities to their maximum potential. The impulse response of waves propagating across HMSs is measured and demonstrates deep sub-wavelength anomalous focusing and on-chip reflectionless negative refraction at the interface of parabolic and hyperbolic media, independent of incident angle. The approach lays the foundation for sub-wavelength imaging in 2D space for the advancement of imaging and wave compression devices, leveraging the capabilities of HMSs.

The development of scalable techniques for large-area growth of layered materials unlocks technological opportunities for the implementation of devices and components suitable for on-chip integration on photonic integrated platforms. Here, terahertz (THz) photoreceivers based on large-area hexagonal boron nitride/single-layer graphene (SLG)/hexagonal boron nitride heterostructures, prepared by chemical vapor deposition and realized by means of an industrially scalable method, are reported. The photo-thermoelectric sensors are integrated on-chip with planar antennas, on-chip radio frequency circuitry, a low-pass hammer-head filter and coplanar strip lines, combining nanosecond response time and large sensitivity. Room temperature responsivities of ≈4 V W⁻¹, with noise equivalent power ≈4 nWHz^−1/2 at high (2.86 THz) frequencies are reached, in a fully frequency-scalable architecture. This paves the way for multiplexed hyperspectral THz cameras and optical communication systems.

The bacterial ecosystem is naturally balanced by viruses known as bacteriophages. Accordingly, they represent an emerging adjuvant to antibiotics to fight bacterial infections. However, the interaction of a single bacterium with bacteriophages remains poorly understood. Here, the use of nanoscale light engineering for the fundamental study of single bacterium-phages interaction is demonstrated. The ability to monitor the lysis of single Escherichia coli cells challenged by two different types of bacteriophages in silicon-on-insulator photonic crystal (PhC) cavities is shown. These nanostructures allow for the optical trapping of a single phage-infected bacterium and their resonant nature allows deciphering the viability of the bacterium by continuously sensing its interaction with the optical field. L3 and H2 PhC cavities are used for the experiments. While the L3 allows for a fine investigation of the bacterial outer membrane, the H2 allows for the optical trapping of the bacterium even after lysis. The analysis of the post-lysis bacterial response provides information that correlates with phage-specific properties. These results, obtained without any need for preliminary labeling nor bioreceptors, deepen the understanding of the fundamentals of bacteria-phages interaction and pave the way to novel breakthrough tools for phage therapy and more generally for antimicrobial susceptibility testing.

Wavefront Shaping

In article 2401985, Kishan Dholakia and co-workers describe high-fidelity projection of structured light through a multimode fiber. The projection of Bessel beams, Airy beams and Laguerre-Gaussian is demonstrated, enabling advanced microscopy technologies at the tip of a hair-thin optical fiber.

N-Heterocyclic Carbene Metallacycles

In article 2401793, Dongjin Qian, Tao Tu, and co-workers achieve tunable full-color fluorescence, featuring white light, based on constrained binuclear N-heterocyclic metallacycles and sulforhodamine B. The co-existence of covalent and coordination bonds within the metallacycles significantly enhance quantum yields and enabling them as versatile, multicolored functional materials.

Pressure-Induced Unusual Transition of Luminescence Mechanics

In article number 2402086, Lingrui Wang, Junnian Chen, Lei Zhang, Haizhong Guo, and co-workers report that (C₆H₁₀N₂)PbBr₄ and (C₆H₁₀N₂)PbCl₄ exhibit excitation-dependent emission enhancement under excitation at 303 nm and 355 nm, highlighting a piezochromic luminescence property. This phenomenon is attributed to lattice compression, which reduces the electron-phonon coupling strength. This work not only offers effective methods to modulate the optical properties of hybrid perovskites but also opens avenues for further exploration of their novel photophysical properties.

A new method is presented for the in vitro detection of glucose using glucose oxidase (GOx) covalently linked to persistent luminescent nanoparticles (PLNPs). This method ensures both sensitive and specific glucose detection by exploiting the enhanced luminescence of PLNPs in the presence of H₂O₂, generated by an enzymatic reaction. To this end, three different PLNPs composed of ZnGa₂O₄:Cr³⁺ (ZGO) nanoparticles are prepared by hydrothermal synthesis at 120 °C for 6 h (ZGO1), 12 h (ZGO2), and 24 h (ZGO3), followed by a calcination at 500 °C, resulting in nanoparticles with an average hydrodynamic diameter of 100 nm ± 5 nm after grinding and centrifugation. These nanoparticles are efficiently covalently functionalized with GOx, via a PEG linker. Following the production of H₂O₂ by the enzymatic reaction between GOx bound to the ZGO surface and glucose present in 100-fold diluted serum, a significant increase in the persistent luminescent signal is observed. This phenomenon is most pronounced for ZGO2, for which a detection limit of 0.01 µm and a detection range from 0.05 to 1 µm is obtained. These results demonstrate the innovative potential of this new technique in glucose monitoring, opening up new avenues for real-time monitoring and effective management of diabetes.