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Optical materials

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The transmission, refractive index, and hardness of optical materials are crucial in determining which window is the best choice for your application. The figure below shows the transmission regions of various materials available as windows.

Material	1ndex 0f Refract10n (nd)	Abbe Number (vd)	Dens1ty	Coefficient of Thermal Expansion 一	S0ften1ng Temp [ºC]	Knoop Hardness	Size Range	Thickness Range
B270	1.523	58.5	2.55	8.2	533	542	5-75x 75mm	1.0- 3.0mm
Barium Fluoride (BaF₂)	1.48	81.61	4.89	18.1	800	82	5- 50mm	1.0- 3.0mm
BOROFLOAT®	1.472	65.7	2.20	3.25	820	480	5- 200mm	1.75- 6.5mm
Calcium Fluoride (CaF₂)	1.434	95.1	3.18	18.85	800	158.3	5- 50mm	1.0- 3.0mm
Germanium (Ge)	4.003	N/A	5.33	6.1	936	780	10 - 75mm	1.0 - 5.0mm
Gorilla® Glass	1.509	N/A	2.44	7.88	843	5100	5-200 *200mm	1.1mm
Magnesium Fluoride (MgF₂)	1.413	106.2	3.18	13.7	1255	415	5 - 50mm	1.0 - 3.0mm
N-BK7	1.517	64.2	2.46	7.1	557	610	5-75x 75mm	0.2 - 4.0mm
Potassium Bromide(KBr)	1.527	33.6	2.75	43	730	7	13 - 50mm	1.0- 5.0mm
Sapphire	1.768	72.2	3.97	5.3	2000	2200	2.5- 75mm	0.5 - 3.2mm
Silicon (Si)	3.422	N/A	2.33	2.55	1500	1150	10 - 50mm	1.0 - 3.0mm
Sodium Chloride (NaCl)	1.491	42.9	2.17	44	801	18.2	13 - 50mm	1.0 - 5.0mm
UV Fused Silica	1.458	67.80	2.20	0.55	1000	500	5-50x 50mm	1.0 - 5.0mm
Zinc Selenide (ZnSe)	2.403	N/A	5.27	7.1	250	120	10 - 75mm	1.0- 6.0mm
Zinc Sulfide (ZnS)	2.631	N/A	5.27	7.6	1525	120	12.5- 50mm

This is the first one.

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