A novel method with high flexibility and efficiency for developing SERS substrates is proposed by patterning nanostructures on Si substrates using focused ion beam direct writing (FIBDW) technology following with precise thermal evaporation of gold film on the substrate. The effect of SERS on the substrate was systematically investigated by optimizing the processing parameters and the gold film thickness. The results proved that small dwell time could improve the machining accuracy and obtain smaller nanogap. The Raman-enhanced performance of the substrate was investigated with 10⁻⁶mol/L Rhodamine 6 G solution. It was indicated that the elliptic nanostructures with 15-nm spacing on Si substrates, coated with approximately 15-nm thick gold film, have exhibited a high-enhanced performance, but dramatic performance degradation was found as the gold film thickness further increased, which most probably resulted from changes of the nanostructures’ morphology such as elliptical tip and spacing. To avoid the morphological changes effectively after depositing gold film, optimization design of the nanostructures for FIBDW on Si substrates was proposed. Besides, a similar phenomenon was found when the gold film was less than 15nm because there was little gold remaining on the substrate. The method proposed in this paper shows a great potential for the higher performance SERS substrates development, which can further reduce the spacing between hot spots.

Multi-modal medical image fusion enhance the representation, aggregation and comprehension of functional and structural information, improving accuracy and efficiency for subsequent analysis. However, lacking explicit cross channel modeling and interaction among modalities results in the loss of details and artifacts. To this end, we propose a novel Explicit Channel-wise Interaction Network for unified multi-modal medical image Fusion, namely ECINFusion. ECINFusion encompasses two components: multi-scale adaptive feature modeling (MAFM) and explicit channel-wise interaction mechanism (ECIM). MAFM leverages adaptive parallel convolution and transformer in multi-scale manner to achieve the global context-aware feature representation. ECIM utilizes the designed multi-head channel-attention mechanism for explicit modeling in channel dimension to accomplish the cross-modal interaction. Besides, we introduce a novel adaptive L-Norm loss, preserving fine-grained details. Experiments demonstrate ECINFusion outperforms state-of-the-art approaches in various medical fusion sub-tasks on different metrics. Furthermore, extended experiments reveal the robust generalization of the proposed in different fusion tasks. In breif, the proposed explicit channel-wise interaction mechanism provides new insight for multi-modal interaction.

Featured by prominent flexibility and fidelity in producing sophisticated stereoscopic structures transdimensionally, three-dimensional (3D) laser printing techniques have vastly extended the toolkit for delivering diverse functional devices. Yet chiral nanoemitters heavily resorting to artificial structures that manifest efficient emission and tightly confined light–matter interactions simultaneously remain alluring but dauntingly challenging for this technique at this moment. In this study, we assert that the chiral photoluminescence is implemented from silver nanostructures with optical duality in one go via a two-fold three-dimensional laser printing scheme. Such laser printing protocol allows the highly desired duality by simultaneously producing uniformly distributed fluorescent silver nanoclusters and aggregated plasmonic silver nanoparticles to tightly confine chiral interactions at the nanoscale. A helical emitter of 550 nm helix-diameter as fabricated has seen a record-high luminescence anisotropic factor with the absolute value up to 0.58, which is two orders of magnitude greater than fluorescent chiral silver clusters. This method holds great promise for future versatile applications in chiroptical nanodevices.

Based on degradable pH-responsive hydrogel, we report on an enhanced three-dimensional data encryption security technique in which a pH value is used for information manipulation. Featuring three types of states upon the pH value variation, namely, shrinkage, expansion and degradation, the hydrogel renders a limited pH value window as the “key” for information decryption. The pH-dependent shrinkage-to-expansion conversion of the hydrogel leads to a threshold pH value for retrieving the recorded data, whilst the degradability of the hydrogel, which can be tuned by adjusting the composition ratio of PEGDA/AAc, gives rise to a second threshold pH value for irreversibly sabotaging the retrieved data. Pre-doping silver ions in the hydrogel facilitates explicit recording and reading of binary data in forms of three-dimensional silver patterns through photoreduction and scattering, respectively, with a femtosecond laser. By accurately matching the vertical spacing of the encoded silver nanopatterns with the diffraction-limited focal depth of the decryption microscope, we can tune the pH value to encrypt and retrieve information recorded in layers and set a critical pH value to smash encoded information, which proves a highly secured 3D data encoding protocol. This strategy can effectively enrich data encryption techniques, vastly enhancing data security within unattained chemical dimensions.