Abstract: A surface plasmon resonance (SPR) instrument is provided, in which light from one or more broad spectrum LEDs is sequentially passed through corresponding apertures directly into a Dove prism. Upon entering the Dove prism the light is refracted onto a surface of the prism against which an SPR sensor is attached, then internally reflects off the surface to a third surface of the Dove prism. Upon exiting the Dove prism the light is again refracted so as to be collinear with the emitted light. The light is collected by an optical fiber, passed through a filter, and conveyed to a detector. The wavelength-angle combination at which SPR occurs is found by using broad spectrum LEDs and a fixed angle. The use of apertures and the omission of collimating lenses allows a more compact SPR instrument than traditional SPR instruments.