Focus isn't just about "sharpness." In laser physics, it's about controlling Irradiance Thresholds. Understanding the hourglass shape allows you to choose between surface destruction and structural color.
Act I: The Geometry
The Rayleigh Range (Beam Shape)
Z-Offset (Height)0.0 mm
Effective Spot
30μm
Beam State
Waist
The Principle: Every laser beam converges to its tightest point (the Waist) and then diverges. The Rayleigh Range defines your vertical depth of field.
Act II: The Thresholds
Ablation vs. Annealing
Height Offset (+Z)+2.0 mm
Peak Irradiance
25%
Surface Interaction
Annealing
Equivalent LPCM
154
Effective DPI
391
Annealing Window:At lower intensity, the metal surface remains intact. Heat drives chromium to the surface to grow a smooth oxide film, creating vibrant interference colors.