Material	Size	Thickness	Refractive index	Material Density	Expansivity	Young’s modulus Knoop	Knoop hardness
Unit	mm	mm	nd(20 °C)	g/cm3	α(20-300 °C)	kN/mm2	HK0.1/20
BOROFLOAT 33	1150 x 850	0.7 - 25.4	1.4714	2.2	3.25 x 10-6 K-1	64	480
D 263T Eco	440 x 360	0.1 - 1.1	1.5231	2.51	7.2 x 10-6 K-1	72.9	590
B 270i	258 x 406	0.7 - 17	1.523	2.56	9.4 x10-6 K-1	71.1	500

Wafer
Sizes:	Typically from 1inch to 4 inch
Thickness:	Typically 0.5mm and 1.0mm
Clear Aperture:	Central 90% of diameter
Flatness:	From 1/4th wave to 2 wave
Parallelism:	From 5 arcsec to 15 arcsec
Surface Quality:	10-5 and 20/10
Rouoghness:	5 angstrom to 10 angstrom
Material:	Quartz,LiTaO3,LiNbO3,MgO doped LiNb
Windows
Sizes:	4mm to 300mm
Thickness:	From 0.3mm to 30mm
Clear Aperture:	Central 90% of diameter
Flatness:	1/10th wave
Parallelism:	1 arcsec
Surface Quality:	20-10 or better
Shapes:	Circular, rectangular and special shapes
Material:	Optical glasses,Fused Silica,B270,D263T,BOROFLOAT33