Abstract: An x-ray focal plane array (XFPA) detector is fabricated by a laser micro-milling method under strict process control conditions. The detector has an array of phosphor pixels bonded together with a light reflective adhesive filling the grooves between adjacent pixels. The phosphor array is bonded on top of a visible detector array, either directly or via a light guiding structure, such that each phosphor pixel is aligned with a corresponding visible detector pixel. The phosphor array is fabricated by moving a phosphor substrate relative to a laser beam of predetermined intensity at a controlled, constant velocity along a predetermined path defining a set of grooves between adjacent pixels so that a predetermined laser flux per unit area is applied to the phosphor material, and repeating the movement for a plurality of passes of the laser beam until the grooves are ablated to a desired depth.