Er:YAG are solid state lasers operating at 2.94 microns wavelength. This wavelength of light is strongly absorbed by water, so Er:YAG lasers are popular in dentistry and surgery. The high pulse power can damage many optics; fortunately, our metal mirrors offer excellent laser damage resistance and have amongst the highest laser damage threshold available for this type of laser.
We regularly supply gold coated copper mirrors for use in articulated arms and hand pieces for dental and medical lasers. The broad spectrum reflectivity of gold means a single arm can be used for several types of infrared lasers, CO2 and Er:YAG for example, without changing optics. Good reflectivity in the visible offers the possibility of using a red or green stain beam along with the infrared beam.
As well as our gold coated copper mirrors, we are sometimes asked to supply uncoated molybdenum mirrors for use with Er:YAG lasers. The reflectivity of polished molybdenum at circa 98% is lower than gold, but the surface of a moly mirror is exceptionally hard and scratch resistant, chemically inert and very durable. However, molybdenum is a difficult metal to machine and profile, limiting the dimensions and styles of mirrors possible. As a raw material it has also become difficult to source in recent years.
For lightweight applications we can supply aluminium based mirrors.
We make mirrors as small as 5mm diameter 1mm thick with full optical specifications. These find uses as mirrors in dental laser hand pieces.
Gold offers R>90% for red light allowing the use of visible alignment techniques to simplify the assembly and adjustment of the articulated arm. We have developed copper mirrors with hardened stainless steel "pads" pressed into copper, for spiked legs to sit on as a datum surface. We also offer gold coated stainless steel mirrors for magnetic mounts.
One customer has reported to us that gold coated copper mirrors can survive pulsed power densities 1,000X greater than that of a typical dental laser.