Joint optimization of quality factor and sensitivity: Research on the performance quantification of two dimensional photonic crystal biosensor

Abstract The two dimensional (2D) photonic crystal (PC) biosensor based on resonant refractive index (RI) sensing has been widely studied due to its high quality factor, strong anti-interference ability, label-free real-time detection and easy integration. However, there is no unified mechanism to compare various PC slab biosensors based on different sensing principles and biological detection targets. Here, we first briefly introduced the definition of detection limit (DL) that is widely accepted, including influence factors such as signal-to-noise ratio, system resolution, and temperature drift. Then, this article focused on calculating and analyzing the influence of quality factor (Q) and sensitivity on DL, and proposed the optimal Q and sensitivity intervals for obtaining extremely low DLs, hoping to provide design strategies for improving the performance of other 2D PC biosensors. Finally, according to the optimal intervals, we performed a joint optimization of Q and sensitivity for the linewidth modulation cavity suitable for the specific detection of small biological targets, and obtained a relatively ideal DL.