Optical and electronic design for a high-performance surface plasmon resonance imager

Surface plasmon resonance (SPR) imaging is a versatile technique for detection, quantification, and visualization of biomolecular binding events which have spatial structure. In this paper, we describe the design principles which we are applying toward the construction of a new high-performance SPR imager. We briefly review the basic principles of SPR biosensing and SPR imaging and discuss the goals for the new design. We focus on two main goals, refractive index (RI) resolution and mechanical simplicity. We address RI resolution as a signal-to-noise issue, using simulations to determine how to maximize the signal (i.e. changes in intensity due to binding events) and minimize the noise. Specific attention is paid to the dominant effects of shot noise. Design concepts for collimating and imaging optics which reduce or eliminate the need for mechanical adjustment are presented. Ray-tracing analysis of the collimating optics is used for detailed analysis of collimator performance.