An apparatus and method for physically separating non-metallic substrates forms a microcrack in the substrate and controllingly propagates the microcrack. An initial mechanical or pulsed laser scribing device forms a microcrack in the substrate. If a pulsed laser is used, it forms a crack inside the substrate that does not extend to either the upper or lower surface. A scribe beam is applied onto the substrate on a separation line. A coolant stream intersects with, or is adjacent to, the trailing edge of the scribe beam. The temperature differential between the heat affected zone of the substrate and the coolant stream propagates the microcrack. Two breaking beams on opposing sides of the separation line follow the coolant stream. The breaking beams create controlled tensile forces that extend the crack to the bottom surface of the substrate for full separation. The scribe and break beams and coolant stream are simultaneously moved relative to the substrate. A preheat beam preheats the heat affected area on the substrate. The beams are formed by an arrangement of lasers and mirrors and lenses. A movable mirror selectively diverts a beam to form either the preheat beam or one or more of the break and scribe beams. Spherical aberration is introduced in the break and scribe beams to flatten their energy distribution profiles and evenly apply the beam energy.