Ⅰ The outstanding characteristics of sapphire window
Sapphire window is a high-performance optical element made of artificial single crystal aluminum oxide (Al₂O₃). Its unique crystal structure gives it a number of breakthrough properties:
1. Extraordinary physical properties
Mohs hardness reaches 9, second only to diamond, and can resist scratches from hard objects such as gravel and metal particles
Bending strength exceeds 1000MPa, more than 5 times that of ordinary glass
The thermal expansion coefficient is only 7.5×10⁻⁶/K, and it remains dimensional stable under drastic temperature changes
2. Broad optical performance
The light transmission range covers deep ultraviolet (150nm) to mid-infrared (5.5μm)
Refractive index 1.76@589nm, birefringence 0.008, suitable for precision optical systems
Surface roughness can reach <5Å, and the maximum light transmittance is up to 85% (uncoated state)
3. Excellent environmental tolerance
Can withstand high temperatures of 2000℃ for a long time in a vacuum environment
Acid and alkali corrosion resistance, can resist all strong acids and alkalis except HF acid
Excellent radiation resistance, suitable for special environments such as the nuclear industry
Ⅱ. Application fields of sapphire windows
1. High-end industrial fields
Semiconductor manufacturing: used for extreme ultraviolet lithography machine observation windows, resistant to plasma corrosion
Oil exploration: pressure-resistant windows for deep well camera systems, withstanding 1000 atmospheres
Aerospace: radiation-resistant windows for satellite optical systems
2. Frontier scientific research applications
Synchronous radiation source: high-transmittance windows for X-ray beams
Quantum computing: superconducting quantum bit protection windows
Fusion devices: first wall observation windows, resistant to high-temperature plasma
3. Civilian high-tech products
Smart phones: flagship models fingerprint recognition protection windows
Medical equipment: endoscope high-transmittance observation windows
Security systems: all-weather surveillance camera protective covers