Plasmonic nanoantennas provide unique opportunities for precise control of light–matter coupling in surface-enhanced infrared absorption (SEIRA) spectroscopy, but most of the resonant systems realized so far suffer from the obstacles of low sensitivity, narrow bandwidth, and asymmetric Fano resonance perturbations. Here, we demonstrated an overcoupled resonator with a high plasmon-molecule coupling coefficient (μ) (OC-Hμ resonator) by precisely controlling the radiation loss channel, the resonator-oscillator coupling channel, and the frequency detuning channel. We observed a strong dependence of the sensing performance on the coupling state, and demonstrated that OC-Hμ resonator has excellent sensing properties of ultra-sensitive (7.25% nm⁻¹), ultra-broadband (3–10 μm), and immune asymmetric Fano lineshapes. These characteristics represent a breakthrough in SEIRA technology and lay the foundation for specific recognition of biomolecules, trace detection, and protein secondary structure analysis using a single array (array size is 100 × 100 µm²). In addition, with the assistance of machine learning, mixture classification, concentration prediction and spectral reconstruction were achieved with the highest accuracy of 100%. Finally, we demonstrated the potential of OC-Hμ resonator for SARS-CoV-2 detection. These findings will promote the wider application of SEIRA technology, while providing new ideas for other enhanced spectroscopy technologies, quantum photonics and studying light–matter interactions.

等离子体纳米天线为表面增强红外吸收（SEIRA）光谱中光与物质耦合的精确控制提供了独特的机会，但迄今为止实现的大多数谐振系统都面临着低灵敏度、窄带宽和不对称法诺共振扰动的障碍。在这里，我们通过精确控制辐射损耗通道、谐振器-振荡器耦合通道和频率失谐通道，展示了具有高等离子体激元分子耦合系数（μ）的过耦合谐振器（OC-Hμ谐振器）。我们观察到传感性能对耦合状态的强烈依赖性，并证明OC-Hμ谐振器具有超灵敏（7.25% nm ^-1 ）、超宽带（3-10 μm）和免疫不对称的优异传感特性法诺线条形状。这些特性代表了SEIRA技术的突破，为使用单个阵列（阵列尺寸为100 × 100 µm ² ）特异性识别生物分子、痕量检测和蛋白质二级结构分析奠定了基础。此外，在机器学习的辅助下，实现了混合物分类、浓度预测和光谱重建，准确率最高可达100%。最后，我们展示了 OC-Hμ 谐振器用于 SARS-CoV-2 检测的潜力。这些发现将促进SEIRA技术的更广泛应用，同时为其他增强光谱技术、量子光子学和研究光与物质相互作用提供新思路。