Lasers and Optoelectronics

Ceramics are specified because of ceramics’ high reflectance at critical wavelengths, e.g. 98%+ reflectance at 1064nm, coupled with exceptional and uniform thermal stability, low electrical loss, resistance to solarisation and oxidation, corrosion resistance to gases and fluids (such as fluorine compounds, CO₂, cooling fluids and cleaning fluids), cleanliness, and hardness. The high reflectance is obtained by a combination of the material properties, microstructure and controlled porosity of the material.

While other materials (such as polymers, polished aluminium, and gold or silver-plated fused silica or glass) can demonstrate the required reflectance at a desired wavelength, they often lack sufficient additional attributes which detrimentally impacts long-term laser quality (e.g., thermal stability, corrosion resistance, cleanliness, durability during maintenance). Furthermore, the reflectors made out of alumina ceramic, e.g., Sintox AL, have high reflectance over a wide range of wavelengths, e.g., 98% reflectance across the wavelength range 500 – 2000nm.

Ceramics components reflect light to concentrate the light energy to amplify an intense, coherent, collimated beam of light at a specific nominal wavelength, a “laser beam.” Because of the high-energy needs of some of these systems, ceramics are often used as electrical feedthroughs for their high electrical resistivities.