Disclosed is a module for efficiently exciting and detecting fluorescence. In a disclosed preferred embodiment, excitation lamp modules with multiple solid-state light sources shone at different oblique angles, such that multiple-beams converge in a single plane, are combined with appropriate emission filters that block the excitation light wavelengths while passing the emission wavelengths. A multitude of such modules can be combined on a slider with precise registration via a mating structure, and can be accurately positioned in front of an observation point, such as a microscope's objective lens, external to the microscope, via a novel magnetic detent system, allowing for the rapid switching between the analysis of different fluorophores.