Hemoglobin concentration sensing via a high-Q-factor Q-BIC-excited heterogeneous dielectric terahertz metasurface
Lingyu Liu1,2,3, Zhongmin Wang4, Weilin Shi1,2,3
1Department of Physics, Capital Normal University, Beijing 100048, China.
Abstract:
A high quality factor (Q factor) heterogeneous all-dielectric terahertz metasurface biosensor, excited by quasi-bound states in the continuum (Q-BIC), was designed and fabricated, and its application for high-sensitivity detection of hemoglobin solutions was demonstrated. Benefiting from the inherently low ohmic losses of dielectric materials, the experimentally measured Q factor of this all-dielectric metasurface biosensor reached 134, revealing a significantly high Q factor (Q >100). In practical applications for detecting hemoglobin solutions, the tri-band all-dielectric terahertz metasurface exhibited a notable redshift phenomenon and showed linear response characteristics relative to changes in concentration. Moreover, this study experimentally verifies the strong localized field confinement capability of bound states in the continuum (BIC). Compared with the non-Q-BIC-governed resonances f1 and f3, the Q-BIC-driven resonance f2 demonstrated significantly enhanced sensing sensitivity. This superior sensing sensitivity of Q-BIC, stemming from its strong field confinement, provides an important reference for the application of Q-BIC-based metasurface biosensing.
