The nanocone-shaped carbon nanotubes field-emitter array (NCNA) is a near-ideal field-emitter array that combines the advantages of geometry and material. In contrast to previous methods of field-emitter array, laser ablation is a low-cost and clean method that does not require any photolithography or wet chemistry. However, nanocone shapes are hard to achieve through laser ablation due to the micrometer-scale focusing spot. Here, we develop an ultraviolet (UV) laser beam patterning technique that is capable of reliably realizing NCNA with a cone-tip radius of ≈300 nm, utilizing optimized beam focusing and unique carbon nanotube–light interaction properties. The patterned array provided smaller turn-on fields (reduced from 2.6 to 1.6 V/μm) in emitters and supported a higher (increased from 10 to 140 mA/cm²) and more stable emission than their unpatterned counterparts. The present technique may be widely applied in the fabrication of high-performance CNTs field-emitter arrays.

Highly confined anisotropic acoustic phonon polaritons in a monolayer α-MoO₃/air nanogap/Au heterostructure largely enhance single molecule detection with nano-FTIR.

A new method of SPR signal amplification based on dynamic field enhancement at the sensor surface to detect C-reactive protein (CRP) is proposed. The gold nanoparticles-detection antibody (AuNPs-dAb) conjugates, as the dynamical agent, were applied to enhance the biosensor sensitivity. The mechanism of SPR sensitivity enhancement is due to the strong evanescent field coupling between the localized SPR (LSPR) of AuNPs and SPR of gold-silver alloy film which proved by COMSOL Multiphysics and MATLAB simulation. The biosensor sensitivity got with sandwich immunoassay (cAb/CRP/AuNPs-dAb) is 5.56-fold of the structure without AuNPs (cAb/CRP/dAb). Moreover, concentration of AuAg-SPR biosensor in CRP detection was lower for an order of magnitude than that of the conventional gold film cladding SPR (Au-SPR) biosensor, according to its direct reaction with the immobilized cAb. The dynamic field enhancement based AuAg-SPR biosensors have high sensitivity in detecting trace biomarker of CRP, and the improvement can also be applied to the detection of other biomarkers in low concentration sensitively.