Subsurface laser engraving is a technique where a laser focuses energy below the surface of a transparent material to create internal marks. The outer surface remains smooth while an image forms inside the object.

The process relies on precise control of focal depth. Each laser pulse produces a microscopic fracture point. Thousands or millions of points combine to create a visible image.

This differs from traditional engraving, which cuts or burns the surface. Instead of removing material, the process changes the optical properties within the object.

Subsurface engraving is widely used for memorial keepsakes, awards, and personalized crystal items.

Cockpit3D is an example of software used to prepare engraving data for subsurface laser systems.