Comparison of sapphire domes, fused silica domes and borosilicate domes

Properties	Sapphire Domes	Fused Silica Domes	Borosilicate Domes
Hardness	Extremely high(Mohs 9)	High(Mohs 7)	Medium(Mohs 6-7)
Transmittance range	0.15-5.5 µm	0.2-2.2 µm	0.3-2.5 µm
High thermal resistance	Excellent(melting point 2050°C)	Good(melting point approx. 1700°C)	Good (softening point approx. 820°C)
Price	High	Relatively high	Lower

What are the advantages of sapphire domes?
Extremely high hardness and wear resistance.
Excellent resistance to high temperatures and chemicals.
High transmittance in a wide band (UV to NIR).
High mechanical strength and impact resistance.

Highly Recommended Optical Domes from Yutai Optics:
Optical Domes
Borosilicate Optical Dome Lens
Infrared Optical Dome Lens
ZnS Optical Dome Lens
LiF Optical Dome Lens
MgF2 Optical Dome Lens
Dome with Flange
Visible BK7 Optical Dome Lens
Ultraviolet Fused Silica Optical Dome Lens