What is plasmon resonance?
Surface plasmon resonance (SPR) is a phenomenon where the electrons in the metal surface layer are excited by photons of incident light with a certain angle of incidence, and then propagate parallel to the metal surface (Fig. 10.17; Zeng et al., 2017).
What factors influence the plasmon resonance frequency?
The factors that influence the plasmon resonance frequency are the dielectric constant of the material and the medium, as well as the geometrical size of the nanostructures.
What is plasmon resonance peak?
The collective oscillation of free electrons in the conduction bands of gold and other noble metals is known as surface plasmon resonance (SPR).
What is the difference between SPR and 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.
What do you mean by LSPR?
However, OpenSPR uses what is known as localized surface plasmon resonance (LSPR). Localized surface plasmon resonance is generated by metal nanoparticles, typically gold or silver, as compared to a continuous film of gold as used in traditional SPR.
How does surface plasmon detect resonance?
Detection is thus accomplished by measuring the changes in the reflected light obtained on a detector. In addition, the amount of surface concentration can be quantified by monitoring the reflected light intensity or tracking the resonance angle shifts.
What causes LSPR?
In LSPR, the electric field component of the incident light interacts with the electrons of each metallic particle, causing the collective electron density to oscillate at a frequency that is resonant with the incoming light.
What is surface plasmon resonance in drug discovery?
Surface plasmon resonance (SPR) is a reliable technique to identify and optimize small molecules that bind to their target proteins with a variety of binding affinities. SPR is used extensively throughout the early drug discovery process from fragment screening to hit prioritization to lead optimization.
Why is P polarized light required for SPR to occur?
Because surface plasmons have only an electric field component, which is normal to the surface, p-polarized light is required to satisfy the boundary conditions necessary to excite SPR. At the SPR angle, the energy of the metal surface coincides with the incident photon and the charge density wave.
What is the role of refractive index in SPR phenomenon?
Technically speaking, SPR refers to an optical phenomenon that enables monitoring of changes in refractive index via a quantum mechanical principle. In a traditional SPR experiment: A target is immobilized or captured onto a surface known as a sensor chip. A pump is used to flow analytes over the sensor chip.
What is multi-parametric surface plasmon resonance (SPR)?
Multi-parametric surface plasmon resonance, a special configuration of SPR, can be used to characterize layers and stacks of layers. Besides binding kinetics, MP-SPR can also provide information on structural changes in terms of layer true thickness and refractive index.
How to increase the sensitivity of a plasmonic sensor?
Here, we engineer the dielectric response of the nanoparticles by alloying a plasmonic material with a weakly dispersive one to yield a negative, but flatter ɛr. This dramatically increases the sensitivity of any plasmonic sensor (of any shape).
How does alloying affect the dielectric function of plasmonic nanomaterials?
We have shown that flattening the dielectric function of plasmonic nanomaterials by alloying results in large LSPR shifts in response to changes in their local environment.
Why use plasmonic nanohelices?
Since the evanescent field of the excited plasmon decays rapidly into the medium, LSPR sensors are ideally suited to making surface-sensitive measurements31. Here we use our chiral plasmonic nanohelices to sense avidin-binding events.