Abstract: Polytetrafluoroethylene (PTFE), or like polymeric material is provided for use as a laser cavity material to efficiently couple flash lamp emissions into the laser medium due to its exceptionally high diffuse reflectance characteristic of better than 99%, which increases the laser output by as much as 100%. In one embodiment, a unique technique for fabricating the cavity includes both sintering and providing an optimal packing density prior to sintering, with the sintering to take place at atmospheric pressure to preserve the optimal packing density as closely as possible in the sintered product. This provides an optimal void percentage for optimal reflectivity. For PTFE, packing densities approaching 1.0 g/cm.sup.3 yield an opaque optimally reflective material.