Toward label-free ultra-high-resolution imaging via wavevector resonance

Abstract

Label-free spatial-frequency-shift (SFS) super-resolution imaging enables nanoscale visualization but fundamentally suffers from a severe trade-off between ultra-high resolution and high signal-to-noise ratio (SNR) when utilizing high-wavevector illumination. To overcome this limitation, recent advancements have introduced an enhanced deep spatial-frequency-shift (EDSFS) mechanism that engineers wavevector resonance with multilayered nanostructures. This approach selectively redistributes and amplifies high-spatial-frequency components, efficiently generating high-wavevector illumination while maintaining strong optical intensity. Consequently, the EDSFS mechanism mitigates the conventional resolution-SNR compromise, achieving sub-diffraction label-free imaging under visible light and significantly extending the coherent transfer function beyond 10/λ with robust fabrication tolerance. Ultimately, this shift from raw wavevector expansion toward the synergistic integration of engineered photonic structures and adaptive computational algorithms paves the way for high-throughput, application-oriented nanoscopic inspection.