title: Spatial resolution in prism-based surface plasmon resonance microscopy.
abstract: Several optical surface sensing techniques, such as Surface Plasmon Resonance (SPR), work by imaging the base of a prism by one of its faces. However, such a fundamental optical concern has not been fully analyzed and understood so far, and spatial resolution remains a critical and controversial issue. In SPR, the propagation length L(x) of the surface plasmon waves has been considered as the limiting factor. Here, we demonstrate that for unoptimized systems geometrical aberrations caused by the prism can be more limiting than the propagation length. By combining line-scan imaging mode with optimized prisms, we access the ultimate lateral resolution which is diffraction-limited by the object light diffusion. We describe several optimized configurations in water and discuss the trade-off between L(x) and sensitivity. The improvement of resolution is confirmed by imaging micro-structured PDMS stamps and individual living eukaryote cells and bacteria on field-of-view from 0.1 to 20 mm(2).
authors.forename: Loïc
authors.initials: L
authors.lastname: Laplatine
authors.forename: Loïc
authors.initials: L
authors.lastname: Leroy
authors.forename: Roberto
authors.initials: R
authors.lastname: Calemczuk
authors.forename: Dieudonné
authors.initials: D
authors.lastname: Baganizi
authors.forename: Patrice N
authors.initials: PN
authors.lastname: Marche
authors.forename: Yoann
authors.initials: Y
authors.lastname: Roupioz
authors.forename: Thierry
authors.initials: T
authors.lastname: Livache
mesh_terms: D004867:Equipment Design; D008853:Microscopy / Q000295:instrumentation*; D020349:Surface Plasmon Resonance / Q000295:instrumentation*