Abstract
Abstract Understanding the spatial radiation pattern in tip-enhanced spectroscopy (TES) is crucial for plasmon-enhanced spectroscopy, chemical analysis and biochemical sensing. Although the TES technique has many excellent advantages, there is still room for improvement in terms of detection sensitivity. In this paper, we theoretically demonstrate the tip-tilted TES configuration featuring high directivity by using side illumination-collection condition. Taking full advantage of the characteristic of high directional emission ascribed to the far-field interference between localized surface plasmon resonance (LSPR) and surface plasmon polariton (SPP) modes, the collection efficiency of TES signals can be largely improved, greatly boosting the detection sensitivity of TES technology. Our theoretical results not only provide a deep understanding of the underlying physical mechanism of the directional surface plasmon-coupled emission of TES, but also serves as a promising guide for the rational construction of a highly efficient TES platform at the single molecular level.
Highlights
Single molecule detection is still one of the key goals of most interface-enhanced spectroscopy studies [1,2,3,4,5,6].Utilizing surface plasmon resonance (SPR) to improve the enhancement factor is a direct way to increase the detection sensitivity
Taking full advantage of the characteristic of high directional emission ascribed to the far-field interference between localized surface plasmon resonance (LSPR) and surface plasmon polariton (SPP) modes, the collection efficiency of tip-enhanced spectroscopy (TES) signals can be largely improved, greatly boosting the detection sensitivity of TES technology
In accordance with the Near-Field to Far-Field (NTFF) transformation method, the directional emission distributions were obtained based on the calculated near-field data at the transformation surface, which is above the tip and parallel to the substrate
Summary
Single molecule detection is still one of the key goals of most interface-enhanced spectroscopy studies [1,2,3,4,5,6]. Utilizing surface plasmon resonance (SPR) to improve the enhancement factor is a direct way to increase the detection sensitivity. A Raman enhancement factor up to 1010 is required to meet the demands of the single molecule detection of probe samples with low scattering cross section [7]. The experimental substrates hardly provide sufficiently high enhancement factors. the intense local electromagnetic field always inevitably destroys portions of target molecules in most cases. Seeking other feasible methods to improve the detection sensitivity is a very urgent task in single molecule studies
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
