The standard 201-100 arc lamp housing, TH3 QTH lamp housing, and SF150 solar simulator has a 1" borosilicate glass collimating lens (fused silica for the SF150). This lens can be upgraded to a 2" borosilicate glass lens or a 2" fused silica lens (for UV applications) to improve light collection efficiency. The resulting aperture from this upgrade is F/1.5. To accommodate this larger size lens, the output port diameter also increases from 1" to 2". For the SF150 Solar simulator, only the 2" fused silica lens upgrade is recommended. Please note that the SF150 Solar Simulator's high speed detector shutter option is not available for this 2" upgrade.
Borosilicate Glass Lens
Any optical piece in the beam path will absorb and distort the output spectrum. When a borosilicate glass lens is used as the collimating lens, it will absorb any harmful ultraviolet light below 360nm. This means only visible and IR light can pass through (λ>360nm).
Fused Silica Lens
For UV applications, the borosilicate glass lens must be upgraded to fused silica version to allow UV wavelengths (λ>200nm) to pass through as well. Please note that some UV lamps produce dangerous levels of ozone, and thus such a lens is also useful to contain the ozone inside the housing. In such cases, water cooling is recommended such that ozone is not blown outside the working environment.