Surface Plasmon Resonance Biosensing
Fig. 1a. (a) Simulated SPR curves for 47-nm- (solid line), 20-nm- (dotted), and 80-nm(dashed) thick Au films illuminated at 633 nm. (b) Simulated curves for a 47-nm-thick Au film at the indicated illumination wavelengths.
Equation (7) assumes that the real () and imaginary () portions of the metal dielectric function are frequency dependent. From these equations, it follows that decreases in the optical frequency will result in less plasmon damping and, hence, longer-range propagation of the plasmon mode [i.e., Eq. (6) decays more slowly]. This effect recently has been exploited by Cornâ€™s group, where IR-excited plasmons are used to obtain higher SPR sensitivity (15,27). Taken alone, the above discussion of the surface plasmon effect suggests the numerous advantages of the technique with respect to biomolecular interaction
Chemistry of metal nanoparticles