Localized surface plasmon resonance biosensing by electro-optic modulation with sensitivity and resolution tunability

The authors demonstrate a localized surface plasmon resonance (LSPR) biosensing technique based on electro-optically modulated attenuated total reflection. Electro-optic effect is utilized to modulate the wavevector of the light for exciting LSPR with the initial wavevector specified by setting the incident angle. The power variation of the attenuated-total-reflected light with the voltage is analyte-dependent and used as indicator to determine analyte concentration. Increasing the voltage has the effects of enlarging the power variation and enhancing the detection resolution. Detection sensitivity depends on the initial light wavevector and can be tuned under various sensing environments for optimal operation. The presented LSPR biosensing possesses the unique features of convenient sensitivity and resolution tunability.