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Hard Gold Coating

Uses of hard gold coated mirrors

Electroplated hard gold coating has excellent and consistent reflectivity in the infrared and good reflectivity in the visible, which allows the easy use of visible alignment lasers. Unlike vacuum deposited hard gold coatings, our electroplated gold never peels, flakes or delaminates.

Polarisation changes to the laser beam on reflection are virtually zero, so for metal cutting and other polarisation sensitive applications, gold mirrors are the most reliable way of maintaining polarisation. Because reflectivity is almost independent of angle of incidence, gold is an excellent choice of coating for scanner mirrors or for mirrors used at varying angles of incidence - collimator mirrors for example.

Electroplated hard gold coating is in intimate thermal contact with the mirror substrate so localised burns, dust and scratches have little effect on the mirror’s performance - ideal for high power carbon dioxide laser cutting.

Electroplated gold is widely used with Er:YAG lasers, CO2 lasers, QCLs, OPOs and many other applications in the infrared from 1-300 microns wavelength, including terahertz imaging.

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Benefits of hard gold coating

Our hard gold coating covers all the mirror surfaces - front sides and rear - so there are no discontinuities that can initiate delamination of the coating. Cassegrain reflectors and Herriot cells use our gold coated metal mirrors because the through holes in the mirror are also gold coated. The coating will withstand typical medical sterilisation procedures.

Chemically deposited hard gold coating has a huge laser damage threshold. With a copper mirror substrate, gold coated mirrors will withstand 40 Kilowatts - see laser damage resistance of CO2 laser optics.

Gold mirrors need careful cleaning, see our technical documents on the subject of cleaning laser mirrors and contamination.

There is a strong technical and economic case for using gold mirrors as beam delivery optics. A survey of used MaxR coated mirrors used for beam delivery has shown that most mirrors regardless of vendor, even if 99.8% reflective when new, are typically 98% reflective.

For more detail on our hard gold coating see our technical data sheet.

The mirrors perfectly match our needs, better than other suppliers. Great job and thanks again for the punctuality in delivery. "

DF – Italy

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