Uses of copper mirrors
Well known as the material of choice for CO2 industrial laser mirrors, they are used in laser metal cutting, laser engraving, and laser welding. Many other infrared applications can also use copper mirrors and they are the most common laser mirror type for high energy and broadband infrared applications.
Because polished copper reflector surfaces react with the atmosphere and lose reflectivity, most, but not all cavity mirrors and beam delivery mirrors are generally used with a coating to improve reflectivity, durability, or alter polarisation on reflection. We offer several metal mirror optical coatings:
- Electroplated gold coated copper mirrors
- MaxR zero phase shift copper mirrors for CO2 laser
- L/4 reflective phase retarder mirror for CO2 laser
- Protected silver coating for broad infrared reflectivity
Benefits of copper mirrors
When freshly polished, uncoated copper mirror surfaces have high natural reflectivity in the infra red, high thermal conductivity and a high heat capacity.
Copper is a crystalline metal, and it’s surface quality and laser damage resistance is limited by the micro crystallinity of the reflective surface. To improve the laser damage resistance and reduce scatter, our copper mirrors have a thin intermediate layer of electroless nickel deposited. Electroless nickel is an amorphous or “glassy”, non crystalline material that can be polished to an exceptional smoothness. Electroless nickel plating also protects the whole of the mirror from oxidation and prevents contamination or reaction of exposed copper with the lasing gas such as in sealed slab discharge resonators.
Laser Beam Products' copper mirrors are chemically polished and the surfaces are super-smooth and free of imperfections from turning lines, fly cutting arcs and diffractive patterns that are common on diamond turned optics. This gives a much higher laser induced damage threshold and a low scatter mirror surface suitable for use in the visible and UV.
Finally, our proprietary stress relieving and heat treatment gives long term stability and performance, across a wide range of operating temperatures.
For the highest laser powers and for maximum stability, internal water cooling channels can be machined into the copper mirror itself.
Designed in features
As copper is readily machinable, we offer a huge range of mirror shapes and sizes such as prisms, axicons, rectangular or square mirrors, chopper wheels, knife edge mirrors and shutter mirrors. By engineering in features such as dowel holes, tapped and helicoiled holes and flanges, a well designed copper mirror can reduce costs for OEMs in mounting, assembly and laser alignment.
Laser Beam Products stock a wide range of copper mirrors with a selection of mirror coatings that are standard replacement parts for the most popular CO2 laser cutting systems. Meeting or exceeding the OEM standards these also cost less, as we are an optical manufacturer. We stock copper mirrors for most European, US and Japanese laser cutting & laser engraving systems.
Copper mirror repair
Used CO2 laser optics can often be reworked to as good as new condition, a service used by a growing number of our customers. The raw metal material in larger mirrors, water cooled mirrors or laser mirrors with complex engineering can be a large part of the cost of the optic, so refurbishment makes economic, technical and environmental sense - contributing to ISO 14000. See our newsletter about reworking used CO2 laser mirrors.