Deep-Focus lenses also allow much thicker materials to be cut at a given laser power.

A Deep-Focus lens has two focal points. The inner portion of a laser beam is intercepted by a section of the lens, of diameter '2h', which has a longer focal length (FL) than the outer part of the lens. The 'basic focal length' is F. The difference in FL is ?F.

This results is high energy density and increased localized temperature at both the upper and the lower foci.