A sample holding device for use in transverse illumination of a sample or sub-components of a sample comprising: a support substrate comprising a sample well adapted to contain and be compatible with said sample wherein said well is provided on at least one wall with an angled reflective surface adjacent said sample well which when in use directs a transverse light beam from a light source through a sample contained within said sample well to provide substantially transverse illumination of a sample contained therein and imaging the sample using a single objective.