Professional Custom Optical Grade Observation Window Rectangle Optical Sapphire Glass Optical Window
Welcome to know about the Sapphire:
Sapphire is composed of alumina, and its crystal structure is hexagonal lattice structure.
Synthetic sapphire common application facets are A-Plane,C-Plane, and R-Plane. Due to the wide optical penetration band of sapphire, it has good light transmission from near ultraviolet (190nm) to mid-infrared. Therefore, it is widely used in optical components, infrared devices, high-intensity laser lens materials.
Sapphire also has the characteristics of high sound velocity, high temperature resistance, corrosion resistance, high hardness, high light transmittance, high melting point (2045℃), etc., so it is often used as a material for photoelectric components.
Properties of Single Crystal Sapphire:
Chemical formula | Al₂O₃ |
Purity | 99.999% |
Crystal structure | Hexagonal |
Density | 3.98g/cm³ |
Hardness Mohs | 9 |
Fusion point | 2045℃ |
Boiling point | 2980℃ |
Coefficient of Thermal Expansion | 5.8×10 -6 /K |
Specific heat | 0.418W.s/g/k |
Thermal conduction | 25.12W/m/k(@100°C) |
Refractive index | no=1.768 ne=1.760 |
dn/dt | 13×10-6/K(@633nm) |
Transmission | T≈80%(0.3-5μm) |
Permittivity | 11.5(//c), 9.3(⊥c) |



Properties of Optical Sapphire Window:
Sapphire Optical Windows are used as viewports to protect other components within an optical assembly, instrument, or laser. In certain applications, optical windows are required to withstand harsh environmental conditions and provide high levels of performance and reliability. Sapphire window has several unique properties that make it the ideal material for these applications.
1. Synthetic Sapphire, the single crystal form of Al2O3, is one of the hardest materials ( 9 Mohs hardness). Because of its structural strength, the sapphire window can be made much thinner than other common optical windows, with better transmittance performance.
2. High thermal stability and excellent thermal conductivity make the sapphire window suitable for the applications in high power. The loss in a sapphire window is less than in another common optical window.
3. Sapphire windows can withstand considerably higher temperatures than most optical windows with zero degradation.
4. Sapphire Windows will not get dark and lose their brilliancy when exposed to UV light.
5. Sapphire windows are extremely stable and resistant to attack by strong acid due to sapphire’s high dielectric constant.
6. Sapphire windows offer wideband transmission from UV to Mid-IR (0.15-5.5µm).
