Surface sensitivity of straight long-range surface plasmon waveguides for attenuation-based biosensing

Abstract

The sensing performance of straight longrange surface plasmon waveguides consisting of a thin gold stripe embedded in Cytop is explored theoretically as a function of the metal stripe cross-sectional dimensions and the length of the sensing channel, and as a function of the sensing medium refractive index. The surface sensitivity and detection limit of such waveguides for attenuation-based biosensing are assessed. We find that changes in coupling efficiency between the sensing waveguide and the access waveguides, and changes in attenuation constant, due to adlayer formation, can contribute additively to the sensing performance. We observed a trade-off between the insertion loss and the change in insertion loss occurring during sensing. Optimum designs leading to compact, sensitive, and cost-effective biosensors are reported.

Straight Long-Range Surface Plasmon Polariton Waveguide Sensor Operating at λ0 = 850 nm

“…Theoretically, a longer sensing length gives a larger output power change for the same analyte. However, the impact of background noise and performance of optical power meter determine an upper limit for the insertion loss of the fluidic section, say, MPA a L a = 30 dB [28]. We then plot in Figure 6 the propagation loss (MPA a ) and the corresponding sensing length (L a ) as a function of Au thickness d for different RI (setting w = 1.5 µm, as mentioned above).…”

Detection of leukemia markers using long-range surface plasmon waveguides functionalized with Protein G

“…23 We also demonstrated the detection of Gramnegative and Gram-positive bacteria in urine. 24 In addition, the sensitivity 25 and optimization 26 of SWG LRSPP sensors has been investigated.…”