Sensing performance optimization of the Bloch surface wave biosensor based on the Bloch impedance-matching method

Area of Science:

• Photonics
• Biosensing
• Nanotechnology

Background:

• Bloch surface waves (BSW) are utilized in biosensors for high sensitivity.
• Optimizing BSW biosensor performance is crucial for enhanced detection capabilities.
• Existing designs may face limitations in sensitivity and signal resolution.

Purpose of the Study:

• To propose a novel strategy for optimizing the sensing performance of Bloch surface wave (BSW) biosensors.
• To enhance the figure of merit (FOM) of BSW biosensors through strategic design.
• To provide a predictable framework for designing high-performance biosensors.

Main Methods:

• Design of a one-dimensional photonic crystal with an omnidirectional photonic bandgap.
• Analysis of Bloch surface wave resonance and its impact on reflection dip characteristics.
• Application of the Bloch impedance-matching method to determine wavelength sensitivity dependence on incident angle.
• Theoretical investigation of system parameters influencing biosensor sensitivity.

Main Results:

• The designed photonic crystal sustains BSW and ensures a narrow reflection dip (FWHM = 0.84 nm).
• Wavelength sensitivity increases as the incident angle decreases towards the critical angle (reaching 1570 nm/RIU at 67.5°).
• The optimized biosensor achieves a high figure of merit (FOM) of 1869 RIU⁻¹.

Conclusions:

• The proposed strategy effectively optimizes BSW biosensor performance.
• The combination of a narrow FWHM and high wavelength sensitivity leads to a significantly improved FOM.
• This work enables the predictable design of high-performance biosensors.