Filamentation cutting made thin glass a manufacturable material

Self-focusing inside the glass creates a column of modified material through the full thickness. The glass then separates along it, with edge strength mechanical scribing never achieved.

By LasersNews Desk·25 Jul 2026·2 min read

In-depth view of advanced laser equipment used for precise engraving and cutting. — Photo by Opt Lasers from Poland on Pexels

Cutting thin, chemically strengthened glass by mechanical scribing produces edge microcracks. In strengthened glass those cracks sit in a surface compression layer over a tensile core, and a crack reaching the tensile zone propagates. Yield and reliability both suffer.

What filamentation does

Focus an ultrashort pulse inside transparent material at sufficient intensity and two effects balance: the Kerr effect focuses the beam further, while plasma generation defocuses it. The result is a self-sustaining filament — a narrow column of high intensity extending far beyond the normal depth of focus.

With appropriate beam shaping, usually a Bessel-like profile, that column extends through the full thickness of the glass in a single pulse, leaving a line of modified material. Repeating along the desired contour creates a perforated plane, and the part separates along it either spontaneously or with slight thermal or mechanical assistance.

Why the edge is better

The separation follows a pre-existing plane of modification rather than propagating a crack from a surface flaw. The resulting edge has fewer and smaller subsurface defects, so edge strength is higher and more consistent.

For display cover glass, that means thinner glass can be used at the same reliability, or the same glass at higher yield. Both matter in a market where cover glass thickness is a design constraint.

Beyond straight lines

Because the process is defined by scanner motion, curves, internal cutouts and chamfered profiles are as accessible as straight cuts. Camera holes and sensor cutouts in display glass are filamentation work.

The limits

Thickness is bounded by how far a filament can be sustained. Highly curved or already-formed glass complicates focus control. Some glass compositions respond poorly, and strengthened glass with steep stress profiles can separate unpredictably.

Where else it went

The technique moved into sapphire, ceramics and semiconductor wafer dicing, wherever a brittle material needs separation without the chipping and kerf loss of a mechanical saw. Display work drove the volume, but the physics was never specific to glass.

This article was produced by the LasersNews AI desk and reviewed by our editors.