What is the Difference Between SPR and LSPR

The key difference between SPR and LSPR is that SPR decay lengths are comparatively longer and more sensitive to interferences, whereas LSPR decay lengths are comparatively shorter and less sensitive to interferences.

The term SPR stands for Surface Plasmon Resonance, whereas the term LSPR stands for Localized Surface Plasmon Resonance. SPR is useful in enhancing the surface sensitivity of several spectroscopic determination nanoscale sensing applications.

CONTENTS

1. Overview and Key Difference
2. What is SPR 
3. What is LSPR
4. SPR vs LSPR in Tabular Form
5. Summary – SPR vs LSPR

What is SPR?

SPR stands for Surface Plasmon Resonance. It is the resonant oscillation of conduction electrons at an interface between the negative and positive permittivity material. This material must be stimulated by incident light. This concept is useful as the basis for most standard tools for the measurement of the adsorption of materials onto a planar metal surface. Or else it can be a surface of metal nanoparticles. SPR is the fundamental concept behind most of the colour-based biosensor applications and in different lab-on-a-chip sensors and diatom photosynthesis.

The surface plasmons are useful in enhancing the surface sensitivity of several spectroscopic determinations, which include fluorescence, Raman scattering, and second harmonic generation. In the simplest way, the SPR can be used for the detection of molecular adsorption, including polymers, DNA< and proteins. In addition, there are some other minor applications which include its use in SPR immunoassay, material characterization, data interpretation, etc.

What is LSPR

The term LSPR stands for Localized Surface Plasmon Resonance. This concept can be defined as collective electron charge oscillations in metallic nanoparticles which are excited by light. These electrons also exhibit an enhanced near-field amplitude at the resonance wavelength. We can observe that this field is highly localized at the nanoparticle, and it tends to rapidly decay away from the nanoparticle or the dielectric interface into the dielectric background. But far-field scattering through the particle is also improved by resonance.

LSP or a localized plasmon can be defined as a result of the confinement of a surface plasmon in a nanoparticle (which has a size that is comparable to the wavelength of the light that is used to excite the plasmon).

What is the Difference Between SPR and LSPR?

The term SPR stands for Surface Plasmon Resonance, whereas the term LSPR stands for Localized Surface Plasmon Resonance. SPR is the resonant oscillation of conduction electrons at an interface between the negative and positive permittivity material. LSRP, on the other hand, is a collective electron charge oscillations in metallic nanoparticles which are excited by light. The key difference between SPR and LSPR is that SPR decay lengths are comparatively longer and more sensitive to interferences, whereas LSPR decay lengths are comparatively shorter and less sensitive to interferences. Moreover, the refractive index of SPR is comparatively much higher than that of LSPR.

The below infographic lists the differences between SPR and LSPR in tabular form for side by side comparison

Summary – SPR vs LSPR

SPR stands for Surface Plasmon Resonance, whereas LSPR stands for Localized Surface Plasmon Resonance. The key difference between SPR and LSPR is that SPR decay lengths are comparatively longer and more sensitive to interferences, whereas LSPR decay lengths are comparatively shorter and less sensitive to interferences. SPR is useful in enhancing the surface sensitivity of several spectroscopic determination nanoscale sensing applications.

Reference:

1. Agrawal A; Cho SH; Zandi O; Ghosh S; Johns RW; Milliron DJ; “Localized Surface PLASMON Resonance in Semiconductor Nanocrystals.” Chemical Reviews, U.S. National Library of Medicine.
2. “Localized Surface Plasmon Resonance.” An Overview | ScienceDirect Topics.

Image Courtesy:

1. “SPR-adsorption-data” By Original uploader was Tomio- at en.wikipedia – Transferred from en.wikipedia (CC BY-SA 3.0) via Commons Wikimedia
2. “LSPR in gold nanoparticles” By M.jodeyri.m – Own work (CC BY-SA 4.0) via Commons Wikimedia