Covert laser marking works until someone photographs it
Micro-features and structural colour resist casual copying. Security comes from verification infrastructure, not from the mark being hard to see.
Manufacturers facing counterfeiting frequently ask about covert laser marking: features too small or too subtle for a counterfeiter to reproduce, verifiable by someone who knows what to look for. Lasers can produce such features. Whether that constitutes protection depends on assumptions worth examining.
What lasers can produce
Micro-text and micro-features. Characters or patterns at sizes requiring magnification to resolve, placed in locations a copier is unlikely to inspect.
Structural colour. Surface structures producing colour by diffraction rather than pigment, with an appearance that changes with viewing angle.
Sub-surface marking. In transparent materials, features created inside the bulk without surface disturbance.
Randomised features. Deliberately random micro-patterns unique to each item, recorded at production and verified against the record — effectively a physical fingerprint.
The security assumption to examine
The first three rely on the counterfeiter not having the same capability. That assumption weakens as the equipment becomes cheaper and more widely available. Ultrafast lasers capable of producing structural colour are commercially available, and a counterfeiter producing high-value goods can afford one.
The fourth is different in kind. A randomised, recorded feature cannot be copied usefully, because copying it produces a duplicate identifier that the verification database will flag. Security comes from the record rather than from the difficulty of reproduction.
Where the effort actually belongs
Verification infrastructure. A covert feature nobody checks provides no protection. A feature checked at distribution, at retail or by the customer, against an authoritative record, does.
That means the marking is the easy part and the database, the verification devices and the process for handling a failed check are the substance.
The realistic position
Covert marking raises the cost of counterfeiting rather than preventing it, which is a legitimate goal. Manufacturers who deployed it successfully generally combined a hard-to-reproduce feature with a verification system and an actual process for acting on failures.
Those who marked covertly and did nothing else generally discovered, some time later, that the counterfeit goods carried the covert feature too.
This article was produced by the LasersNews AI desk and reviewed by our editors.
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