This paper proposes a patterned material composed of two types of photonic crystals based on CdS and SiO2 nanoparticles. We combined the photonic crystals with poly(ethylene glycol) diacrylate (PEGDA) by nanoparticle self-assembly and UV curing and successfully formed a material containing the different photonic crystals. The material prepared contains two kinds of photonic crystals with different refractive indices, CdS and SiO2 nanoparticles, and due to the large difference in refractive indices of the two materials, the reflection wavelengths of the photonic crystals composed of the two materials also have disparities when the incident angle changes. Macroscopically, the structural colors of the two photonic crystals change with the change in incident angle. In response to this phenomenon, we designed a variety of applications based on a multiangle patterned photonic crystal film to achieve a variety of information storage functions by changing the incident angle and, through the angle change, to achieve lipstick logo, mobile phone bar code, and antipeeping keyboard applications.
Surface plasmon resonance (SPR), generally including propagating SPR (PSPR) and localized SPR (LSPR), has attracted wide attention due to the uniqueness of the strong evanescent field. The PSPR has the merit of high sensitivity over the LSPR, but lacks flexibility to tune resonant wavelength and serves limited application. Here we revisit the fundamental PSPR wavevector matching theory and construct a three-dimensional (3D) tuning hypersurface for the parameters of resonant wavelength, incident angle, and surrounding refractive index , which provides the performance tuning guide map. With assistance of the hypersurface, a hypersurface-tuning PSPR (HT-PSPR) sensor is designed with high sensitivity and ultra-wide detection range. Experiments demonstrate that the sensor can selectively tune the resonance and render the sensitivity to a theoretical upper limit of ∼10 5 nm/RIU, or an ultra-wide detection range of 0.518 RIU, which satisfies the requirement for most gas and liquid sensing applications. Using D -biotin as the detection sample of small molecule (MW=244 Da), the HT-PSPR sensor achieves an ultra-low detection limit down to 27.5 fM. The hypersurface-tuning has created an intrinsic, universal and flexible method for tuning PSPR at the desired resonant wavelength, sensitivity and detection range, which is expected to find great significance in SPR design and applications.