Plasmon enhanced fluorescence microscopy below quantum noise limit with reduced photobleaching effect

Abstract

We propose a plasmon enhanced fluorescence microscopy technique below the quantum noise limit. This is achieved by exciting fluorescent molecules with photon number squeezed (PNS) light and using nanoparticles as an enhancer for overcoming the low absorption cross section. PNS light has an inherent sub-Poissonian photon distribution for which the variance Δn<⟨n⟩. PNS light has the added advantage of antibunching, which eliminates photobleaching due to higher order photon interactions. We anticipate that single molecule studies will benefit from such a radiation source.

Surface Plasmon-Assisted Fluorescence Enhancing and Quenching: From Theory to Application

“…By coupling with surface plasmons, the fluorescence emission of excited-state fluorophores is accordingly directed into the prism substrate at a narrow angle for a signal being integrally collected. − This SPCE-based approach can provide up to 50% light collection efficiency, inducing a great fluorescence performance. , Nevertheless, there is still a fluorescence quenching zone in close vicinity to the metallic surface. Therefore, an appropriate spacing layer is required in SPCE measurements .…”

“…106−108 This SPCE-based approach can provide up to 50% light collection efficiency, inducing a great fluorescence performance. 109,110 Nevertheless, there is still a fluorescence quenching zone in close vicinity to the metallic surface. Therefore, an appropriate spacing layer is required in SPCE measurements.…”

Multiple excitation nano-spot generation and confocal detection for far-field microscopy

“…10,11 Most of the PSF employed in single-and multi-photon microscopy can produce single excitation spots suitable for point-by-point scanning, making the imaging process time-consuming and prone to photobleaching. 12,13,14 In this report, we propose an excitation technique for generating multi-spot excitation PSFs. The excitation multi-spot PSF is generated by the interference of two counter-propagating depth-of-focus PSFs as shown in Fig.…”