biostudies-literatureMa LNational Natural Science Foundation of China (National Science Foundation of China)8503https://www.ebi.ac.uk/biostudies/studies/S-EPMC12475147biostudies-literatureUnknown16(1)Lower-frequency characteristics of the terahertz regime confer advantageous low photon energy for biochemical sensing while imposing inherent sensitivity constraints. Here, we demonstrate a terahertz asynchronous twin-comb sensor and an extra-spectrum sensing mechanism through cascading microchannel architecture within a metallic waveguide. The extra-spectrum sensing prefigures an enhanced sensitivity of 4 orders of magnitude compared to existing terahertz biosensing and surpasses its counterpart in the optical band. Hypersensitivities of 0.398 GHz mm² pg^-1 in trace detection manifest through the located characteristic resonance frequency beyond the spectrum domain. Additionally, we observed the photoisomerization of azo dye in the terahertz band with a photoresponse sensitivity of 0.91 GHz cm² mW^-1, opening possibilities for photoactive material-assisted terahertz sensors. In summary, we instantiate an asynchronous twin-comb sensing beyond the spectrum domain, offering a perspective for ultrasensitive sensing, and promising applications in optical frequency comb precision metrology, artificial intelligence photonics, and integrated sensing and communications.Nature communicationsTerahertz asynchronous twin-comb for prefiguring hypersensitivity beyond spectrum domain.PMC124751476220516062371258624B20756233501262435010Fan FMa LFeng JShen PSong CJi YWang XChang SfalseTerahertz asynchronous twin-comb for prefiguring hypersensitivity beyond spectrum domain.Lower-frequency characteristics of the terahertz regime confer advantageous low photon energy for biochemical sensing while imposing inherent sensitivity constraints. Here, we demonstrate a terahertz asynchronous twin-comb sensor and an extra-spectrum sensing mechanism through cascading microchannel architecture within a metallic waveguide. The extra-spectrum sensing prefigures an enhanced sensitivity of 4 orders of magnitude compared to existing terahertz biosensing and surpasses its counterpart in the optical band. Hypersensitivities of 0.398 GHz mm² pg^-1 in trace detection manifest through the located characteristic resonance frequency beyond the spectrum domain. Additionally, we observed the photoisomerization of azo dye in the terahertz band with a photoresponse sensitivity of 0.91 GHz cm² mW^-1, opening possibilities for photoactive material-assisted terahertz sensors. In summary, we instantiate an asynchronous twin-comb sensing beyond the spectrum domain, offering a perspective for ultrasensitive sensing, and promising applications in optical frequency comb precision metrology, artificial intelligence photonics, and integrated sensing and communications.2025-01-01T00:00:00Z2025 Sep2026-06-03T21:34:57.867Z2026-05-02T03:07:56.821ZS-EPMC124751474100629610.1038/s41467-025-63513-z