Why choose the BK7 (K9) window?
Cost effective: lower cost than fused silica and sapphire, suitable for visible and near-infrared applications.
Sophisticated processing: easy to cut, polish and coat, suitable for mass production.


What is the internal transmittance of BK7 (K9)?

内部透过率  Internal Transmittance T
λ（ nm）		τ (5mm)		τ (10mm)	λ（ nm）		τ (5mm)		τ (10mm)
2400		0.842		0.709	480		0.998		0.997
2200		0.882		0.778	460		0.998		0.997
2000		0.951		0.904	440		0.998		0.997
1800		0.978		0.957	420		0.998		0.997
1600		0.993		0.987	400		0.998		0.997
1400		0.988		0.975	390		0.998		0.996
1200		0.999		0.998	380		0.997		0.995
1060		0.999		0.998	370		0.997		0.995
1000		0.999		0.998	360		0.996		0.992
950		0.999		0.998	350		0.991		0.982
900		0.999		0.998	340		0.987		0.974
850		0.999		0.998	330		0.975		0.951
800		0.999		0.998	320		0.946		0.894
700		0.998		0.997	310		0.881		0.776
650		0.998		0.997	300		0.746		0.557
600		0.998		0.997	290		0.524		0.275
550		0.998		0.997	280
500		0.998		0.997