Theoretical Understanding of an Absorption-Based Surface Plasmon Resonance Sensor Based on Kretchmann's Theory

Abstract

An optical-absorption-based surface plasmon resonance (SPR) sensor is proposed, and its theoretical aspects are discussed in terms of mathematical descriptions and numerical simulations of the SPR curve. The response theory of the absorption-based SPR sensing is based on the expansion of Kretchmann's SPR theory into the case in which optical absorption in the sensing layer is expressed by the Lorentz model. The numerical simulations were performed using a three-layer Fresnel equation of p-polarization. It was found that SPR curve behavior of the absorption-based SPR sensor depends on the frequency relation between the light source and the optical absorption and the thickness of the metal layer. The SPR curve behavior is divided into three types according to the large, small, and equal relations between excitation and absorption frequencies. Each type of behavior is further divided into two types that are due to thin and thick metal layers. The theory of this new type of sensor based on optical absorption was explained and demonstrated by the simulation of the SPR curves using optical parameters relating to a silver-metal-based SPR sensor.

Dependence of the signal amplification potential of colloidal gold nanoparticles on resonance wavelength in surface plasmon resonance-based detection

“…The SPR signal (reported as a function of particle surface coverage), varies for the resonance wavelengths of approximately 650 nm, 770 nm, and 920 nm, and is greatest at 770 nm. Modeling results using a simple absorptive Lorentz model [11,12] are shown to be in good agreement with the experimental data and are consistent with a red-shifted localized surface plasmon resonance (LSPR) absorption peak of 650 nm for the colloidal gold nanoparticles on planar gold. The results indicate that the resonance wavelength dependence of the colloidal gold nanoparticles on planar gold is a balance between this LSPR absorption peak in the visible range and the inherent sensitivity increase of SPR on planar gold in the NIR [13,14].…”

SPR sensor signal amplification based on dye-doped polymer particles

“…A simulation of the SPR curve change based on absorption changes of the sensing layer was performed in order to estimate the effect of the dye [17][18][19][20].…”

“…Ion-optode membranes [14][15][16] were used as SPR-sensing layers. Based on the change of the color of a membrane-incorporated indicator dye, small molecules were successfully measured due to the change of the imaginary part of the surface refractive index [17][18][19][20].…”

Strongly coupled bio-plasmonic system: Application to oxygen sensing

“…However, past studies have reported an enhancement in the sensitivity, if the antibody coating layer used for the detection of a specific antigen has an absorption band in the vicinity of the SPR resonance. [13][14][15][16][17] Moreover, Nakkach et al showed that the reflectivity variation can be enhanced by a factor of almost 160% by using appropriate dye molecules conjugated to the analyte (in this case DNA). 17 It is worth mentioning that in these studies strong interaction or coupling between the absorption bands of the antibody layer and the surface plasmon was not observed.…”

“…17 It is worth mentioning that in these studies strong interaction or coupling between the absorption bands of the antibody layer and the surface plasmon was not observed. 13,[15][16][17] On the other hand, several studies have dealt with strong coupling between surface plasmons and strongly absorbing dye molecule but these studies have not illustrated how the strong coupling phenomenon is favorable for sensing applications. [18][19][20][21][22][23] The phenomenon of strong coupling, which is typically characterized by an anti-crossing or avoided boundary crossing, is very well known and has been observed in different physical systems like cavity QED, [24][25][26][27][28][29] plasmonics, and photonics [30][31][32][33] and has been applied for the development of practical applications like plasmonic switches 34 and optical rulers.…”