Laser system and method forming a high purity fused silica glass sheet with micro-crenellations

A high purity fused silica glass sheet, comprising:

• a first major surface;
• a second major surface opposite the first major surface;
• at least 99.9 mole % silica, wherein the silica is at least generally amorphous, having less than 1% crystalline content by weight;
• and
• an average thickness between the first major surface and the second major surface of less than 500 um;
• wherein the first major surface, in cross section, has tiny notches along the first major surface, wherein at least ten of the tiny notches have:
• a depth that is at least 25 nm and no more than 1 um measured relative to a higher one of adjoining local caps on either side of the respective notch,
• a width between adjoining local caps that is at least 5 um, and
• a length of at least 500 um;
• wherein the tiny notches curve along the length thereof, and
• wherein the notches are crenellated such that at least some of the notches have generally flat bottom surfaces and at least some respective adjoining caps have generally plateau top surfaces offset from the bottom surfaces by steeply-angled sidewalls.