Angle-dependent resonance of localized and propagating surface plasmons in microhole arrays for enhanced biosensing

Abstract

The presence of microhole arrays in thin Au films is suited for the excitation of localized and propagating surface plasmon (SP) modes. Conditions can be established to excite a resonance between the localized and propagating SP modes, which further enhanced the local electromagnetic (EM) field. The co-excitation of localized and propagating SP modes depends on the angle of incidence (θ(exc)) and refractive index of the solution interrogated. As a consequence of the enhanced EM field, enhanced sensitivity and an improved response for binding events by about a factor of 3 to 5 was observed with SPR sensors in the Kretschmann configuration for a set of experimental conditions (λ(SPR), θ(exc), and η). Thus, microhole arrays can improve sensing applications of SPR based on classical prism-based instrumentation and are suited for SP-coupled spectroscopic techniques.

Plasmonic Enhancement by a Continuous Gold Underlayer: Application to SERS Sensing

“…This coupling has been already shown experimentally and demonstrated for samples with a glass substrate with a SiO2 spacer between gold nanodisks and gold film [35,42]. The possibility to have the excitation of localized and propagating surface plasmon modes can be also obtained with microhole arrays in thin Au films [43]. EFs increase from 633 nm to 785 nm by a factor around 10, which is in good agreement with previous results showing the importance of the excitation wavelength as function of the diameter [44] for disks.…”

Recent advances in surface plasmon resonance imaging: detection speed, sensitivity, and portability

“…In addition, the authors could adjust the array dimensions and the thickness of the gold layer for resonance tuning. Large-scale gold microhole and nanohole arrays as well as silver nanocave arrays have also been fabricated and demonstrated for highly sensitive refractive index sensing [101][102][103][104]. Dou et al reported a simple and scalable colloidal lithography technology for fabricating gold nanodonuts, which demonstrated a high SPR sensitivity of ~758 nm/RIU [105].…”

Recent advances in plasmonic nanostructures for sensing: a review

“…110,108 This tunability for a particular application of interest allows for dramatic increases in SPR sensitivity. 107,[118][119][120] Although the tunability of such nanoarrays in gold is limited to the NIR and longer wavelength region of the visible (i.e., ∼500 nm or greater), a variation of these nanoslit and nanohole arrays, known as nanotriangle arrays [see Fig. 8(f)], 107 has demonstrated the ability to further expand the range of LSPR wavelengths achievable simply by altering the structure.…”