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Linearly polarized organic light-emitting diodes have become appealing functional expansions of polarization optics and optoelectronic applications. However, the current linearly polarized diodes exhibit low polarization performance, cost-prohibitive process, and monochromatic modulation limit. Herein, we develop a switchable dual-color orthogonal linear polarization mode in organic light-emitting diode, based on a dielectric/metal nanograting-waveguide hybrid-microcavity using cost-efficient laser interference lithography and vacuum thermal evaporation. This acquired diode presents a transverse-electric/transverse-magnetic polarization extinction ratio of 15.8 dB with a divergence angle of ±30°, an external quantum efficiency of 2.25%, and orthogonal polarized colors from green to sky-blue. This rasterization of dielectric/metal-cathode further satisfies momentum matching between waveguide and air mode, diffracting both the targeted sky-blue transverse-electric mode and the off-confined green transverse-magnetic mode. Therefore, a polarization-encrypted colorful optical image is proposed, representing a significant step toward the low-cost high-performance linearly polarized light-emitting diodes and electrically-inspired polarization encryption for color images. The authors present a switchable dual colour orthogonal linear polarized OLED by internally integrating a nanograting for selective diffraction of optical modes, which is appealing for applications including polarisation-encrypted colourful optical images and autostereoscopic naked-eye 3D displays.

Multiferroic materials have great potential in non-volatile devices for low-power and ultra-high density information storage, owing to their unique characteristic of coexisting ferroelectric and ferromagnetic orders. The effective manipulation of their intrinsic anisotropy makes it promising to control multiple degrees of the storage “medium”. Here, we have discovered intriguing in-plane electrical and magnetic anisotropies in van der Waals (vdW) multiferroic CuCrP 2 S 6 . The uniaxial anisotropies of current rectifications, magnetic properties and magnon modes are demonstrated and manipulated by electric direction/polarity, temperature variation and magnetic field. More important, we have discovered the spin-flop transition corresponding to specific resonance modes, and determined the anisotropy parameters by consistent model fittings and theoretical calculations. Our work provides in-depth investigation and quantitative analysis of electrical and magnetic anisotropies with the same easy axis in vdW multiferroics, which will stimulate potential device applications of artificial bionic synapses, multi-terminal spintronic chips and magnetoelectric devices. Manipulating electrical and magnetic anisotropies will stimulate multi-terminal device applications. Here, the authors discover axis dependence of current rectifications, magnetic properties and magnon modes in van der Waals multiferroic CuCrP 2 S 6 .

Physically unclonable functions (PUFs) are critical security primitives used in authentication and cryptographic key generation. Among these, structural color-based PUFs offer distinct advantages, including fade resistance and the ability to conceal multi-dimensional information. However, current fabrication methods rely heavily on wet processes and laser ablation. Consequently, there is a significant need for flexible PUF labels capable of being produced through a facile and dry process. Here, we present stress-relief modulated photonic crystal PUF labels designed for multi-level dynamic encryption. We achieve random patterning of nanograting-based photonic crystals by leveraging curved pinning edge-induced interruptions and the uncontrolled bulking of the polymeric elastomer due to the uneven adhesion force from the tape. Using artificial intelligence-based deep learning algorithms, we authenticate the labels by extracting structural color, brightness, and saturation, which are determined by the grating periodicity, depth, and orderliness of each pixel. Furthermore, we integrated these photonic crystal patterns with dynamically modulated optical erasure to extend encryption capacity from the spatial to the temporal dimension. We anticipate this approach will enable advanced wearable anti-counterfeiting labels and multi-level digital encryption systems.

Multi-wavelength random lasers with switchable modes have advantages in the fields of novel light source and information security. Here, we propose a dual-wavelength phase transition random laser, which can modulate lasing modes arbitrarily assisted by the phase transition hydrogel. Once the phase transition occurs in hydrogel, the scattering properties of light in the random system changes, affecting the optical feedback mechanism and enabling reversible switching of the dual-wavelength random laser mode between incoherent and coherent states. More appealing, random lasing mixed incoherent mode and coherent mode have been obtained for the first time by controlling the local phase transition of the sample. Based on these properties, an information encryption system is constructed by encoding spectral fingerprints at different modes. This work provides an effective way to precisely control the output modes at different wavelengths in the multi-wavelength random laser, further expanding the application of random lasers in multifunctional light sources, color imaging, and information safety.

Highlights Nanoimprint lithography (NIL) enables high-performance light management in organic light-emitting diodes and organic solar cells, and enhances charge transport in organic field-effect transistors via controlled molecular ordering, pushing organic optoelectronics beyond conventional efficiency limits. The technology provides a scalable, low-cost platform for large-area fabrication on flexible substrates, effectively bridging the gap between laboratory innovation and industrial mass production. NIL uniquely empowers the creation of multifunctional integrated devices and novel architectures, opening pathways for next-generation wearable electronics and bio-integrated systems. Organic optoelectronic devices demonstrate immense potential in flexible displays, wearable electronics, and artificial skin, needing precise light-field and morphology management strategies to further improve their opto-electric performance. Nanoimprint lithography (NIL) has emerged as a high-resolution, high-efficiency, and low-cost patterning technique that mechanically transferring micro/nanoscale patterns from a template to a substrate to significantly enhance the optoelectronic performance through the precise creation of advanced light-management structures, combined with additional solid-state stacking morphology. This review systematically summarizes recent advances in NIL technology for organic optoelectronics. It begins with an introduction to the fundamental principles, main process variants (thermal, ultraviolet, and electrochemical NIL), as well as key technical issues. Subsequently, through specific applications in organic light-emitting diodes, organic solar cells, and organic field-effect transistors, it highlights the exceptional capabilities of NIL to enhance device performance by controlling crystallization and creating functional micro/nanostructuring. Specific advantages include enabling high-efficiency light management to overcome efficiency bottlenecks, facilitating low-cost, high-throughput manufacturing for industrialization, full compatibility with flexible substrates for emerging applications, enabling multifunctional integration and novel device architectures, and tailoring material microstructures and properties advance fundamental research. Finally, we discuss the remaining challenges and future prospects of NIL in integrated organic optoelectronic systems.

Hall-effect in semiconductors has wide applications for magnetic field sensing. Yet, a standard Hall sensor retains two problems: its linearity is affected by the non-uniformity of the current distribution; the sensitivity is bias-dependent, with linearity decreasing with increasing bias current. In order to improve the performance, we here propose a novel structure which realizes bias-free, photo-induced Hall sensors. The system consists of a semi-transparent metal Pt and a semiconductor Si or GaAs to form a Schottky contact. We systematically compared the photo-induced Schottky behaviors and Hall effects without net current flowing, depending on various magnetic fields, light intensities and wavelengths of Pt/GaAs and Pt/Si junctions. The electrical characteristics of the Schottky photo-diodes were fitted to obtain the barrier height as a function of light intensity. We show that the open-circuit Hall voltage of Pt/GaAs junction is orders of magnitude lower than that of Pt/Si, and the barrier height of GaAs is smaller. It should be attributed to the surface states in GaAs which block the carrier drifting. This work not only realizes the physical investigations of photo-induced Hall effects in Pt/GaAs and Pt/Si Schottky junctions, but also opens a new pathway for bias-free magnetic sensing with high linearity and sensitivity comparing to commercial Hall-sensors.

Fabrication of cross‐scaled ultrasensitive surface‐enhanced Raman scattering (SERS) substrates ranging from nanogaps for efficient localized surface plasmon resonances (LSPRs) to mm2‐size for easy operation is challenging. Here, we propose femtosecond‐laser‐induced periodic phase‐transition (fs‐LIPPT) of 1T’‐MoTe2 nanograting template, inducing Au nanostructures for frequency‐shift digital‐SERS immunoassay. The interference between the incident transverse electric wave and propagation wave in the 2H‐MoTe2/SiO2‐interlayer waveguide triggers the highly homogeneous periodic 1T’ phase‐transition pattern. The Au nanoparticles (AuNPs) are subsequently reduced at the 1T’ regions in chloroauric acid solution, forming a subwavelength AuNPs@1T’‐MoTe2 nanograting with 295.0 ± 8.1 nm in period. The Fano resonances by coupling the narrow‐band guided‐mode resonances supported in the 1T’‐MoTe2/SiO2‐interlayer nanograting with the broadband LSPRs in AuNPs promote optical localization, achieving the superior performance with a limit of detection in 10−14 m and a SERS performance factor of 7.5 × 106 for rhodamine 6G (R6G). A paradigm of frequency‐shift digital‐SERS immunoassay for serological diagnosis is established using the R6G‐labeled AuNPs@1T’‐MoTe2 nanograting conjugated with immunoglobulin G of rheumatoid arthritis, by which the discrimination accuracy is unexpectedly close to unity. The present work provides a novel protocol for SERS serum immunoassay, opening opportunities for early diagnosis and accurate prognosis of autoimmune diseases by blood test in the future. A protocol of fs‐laser‐induced periodic phase‐transition of 2D‐MoTe2 template, inducing AuNPs@1T’‐MoTe2 nanograting, is developed. The labeled AuNPs@1T’‐MoTe2 substrate conjugated with specialized immunoglobulin G demonstrates an unexpectedly high discrimination accuracy close to unity for serological diagnosis of rheumatoid arthritis by frequency‐shift digital‐SERS immunoassay. The present work paves a simple way to achieve early diagnosis and accurate prognosis of autoimmune diseases by blood test.

Enantiomeric excess (ee) is an essential indicator of chiral drug purification in the pharmaceutical industry. However, to date the ee determination of unknown concentration enantiomers generally involves two separate techniques for chirality and concentration measurement. Here, a whispering‐gallery mode (WGM) based optofluidic microlaser near exceptional point to achieve the ee determination under unknown concentration with a single technique is proposed. Exceptional point induces the unidirectional WGM lasing, providing the optofluidic microlaser with the novel capability to measure chirality by polarization, in addition to wavelength‐based concentration detection. The dual‐parameters detection of optofluidic microlaser empowers it to achieve ee determination of various unknown enantiomers without additional concentration measurements, a feat that is challenging to accomplish with other methods. Featuring the sensitivity enhancement and miniature structure of the WGM sensors, the obtained chiroptical response of the present approach is ≈30‐fold higher than that of the conventional optical rotation‐based polarimeter, and the reagent consumption is reduced by three orders of magnitude. By inducing the exceptional point, the whispering‐gallery mode‐based optofluidic microlaser is enhanced with the novel capability to measure chirality of enantiomer by polarization, in addition to wavelength‐based concentration detection. The dual‐parameters detection of optofluidic microlaser empowers it to achieve enantiomeric excess determination of various unknown enantiomers by a single technique, a feat that is challenging to accomplish with other methods.

Bidirectional displays, capable of simultaneous front and rear illumination, enable transformative applications such as see‐through retail displays, intelligent signage, and next‐generation foldable devices. Despite their potential, the inherent trade‐off between transparency and brightness, coupled with imbalanced bidirectional emission, has hindered the advancement of bidirectional viewing organic light‐emitting diodes (BV‐OLEDs). Here, we present a dual‐approach strategy to achieve simultaneously improved and balanced bidirectional emission with quasi‐Lambertian distribution in bidirectional emitting OLEDs. By combining a microcavity resonance enhancement through nano‐patterned structures and a dielectric/metal/dielectric (DMD) capping layer for improved top electrode transmittance, we effectively suppress surface plasmon and waveguide modes in OLED devices. Consequently, the optimized nanoimprinted DMD electrode achieved a remarkable 89.7% enhancement in transmittance (from 33.9% to 64.3% at 664 nm) compared to conventional planar electrodes; and the resulting BV‐OLED demonstrated balanced bidirectional emission from 33% to 42% with a 67.3% total brightness increase, while exhibiting enhanced transparency with nearly zero haze, quasi‐Lambertian radiation pattern, and excellent color stability across a 120° viewing angle. This breakthrough establishes a fundamental design framework for bidirectional displays, bridging conventional dual‐panel technologies with emerging applications in next‐generation transparent and flexible display systems. We present a dual‐approach strategy for high‐performance bidirectional‐viewing OLEDs, combining enhanced cavity resonance with a nanoimprinted dielectric/metal/dielectric (DMD) electrode. This bidirectional viewing OLED presents an 89.7% enhanced electrode transmittance, a balanced bidirectional emission ratio with 67.3% total brightness increase, as well as quasi‐Lambertian distribution featuring zero haze and stable color performance within 120° viewing angle.

Single mode lasers, particularly red-green-blue (RGB) colors, have attracted wide attention due to their potential applications in the photonic field. Here, we realize the RGB single mode lasing in a hybrid two-dimension and three-dimension (2D–3D) hybrid microcavity (μ-cavity) with a low threshold. The hybrid 2D–3D μ-cavity consists of a polymer fiber and a microsphere. Typical RGB polymer film consisting gain materials are cladded on a fiber. To achieve single mode lasing, the polymer fiber therein serves as an excellent gain cavity to provide multiple lasing modes while the microsphere acts as a loss channel to suppress most of the lasing modes. Mode switching can be realized by adjusting the pump position. It can be attributed to the change of coupled efficiency between gain μ-cavity and loss μ-cavity. Our work will provide a platform for the rational design of nanophotonic devices and on-chip communication.