An apparatus for large-scale dynamic imaging of a sample is described. The apparatus includes an optical detector, a light guide, a dichroic beam splitter, and a light source. The light guide includes a first portion and a second portion. The second defines a tapered shape such that a first diameter defined by a distal end of the second portion is smaller than a second diameter defined by a proximal end of the second portion. The dichroic beam splitter is positioned between the first portion and the second portion of the light guide. The light source is configured to direct a light beam through an external surface of the dichroic beam splitter. The dichroic beam splitter is configured to direct the light beam toward the second open end of the light guide and transfer the return emitted signal through the light guide to the optical detector.