Lasers need ceramic and glass components for applications needing dimensional stability. Ceramic and glass components are known for their durability and high reflectivity and are often used for insulation purposes and as reflectors in high power laser cavities. A key advantage of glass and ceramic materials is that they have a lower Coefficient of Thermal Expansion vs. metals. Overall, there is a huge thermal advantage in using glass and ceramic materials over traditional metals. Different materials are chosen for different excimer, solid state, CO2, Ion, He-Ne lasers. Laser cavity for both glazed and unglazed, and with different active media like dry and liquid media can be designed.