| Basic Properties |
| Crystal structure |
Hexagonal System |
Cubic |
cubic |
| Lattice |
a=4.785, C=12.991 |
|
a=5.462 |
| Density |
3.98g/cm3 |
4.5g/cm3 |
3.18 g/cm3 |
| Transmission Range |
150~5500nm |
250~5000nm |
170 nm~7800 nm |
| Melting Point |
2040 °C |
1970 °C |
1360 °C |
| Specific Heat |
0.418 W.s/g/K |
0.59 W.s/g/K |
|
| Thermal Conductivity |
25.12 W/m/K |
14 W/m/K |
9.71W/m/K |
| Thermal Shock Resistance |
790 W/m |
790 W/m |
|
| Thermal Expansion Coefficient |
5.8x10-6 /K |
6.9x10-6 /K |
18.85X10-6 /K |
| dn/dt, @633nm |
13x10-6 /K |
7.3x10-6 /K -1 |
|
| Mohs Hardness |
9 |
8.5 |
6 |
| Refractive Index |
1.83 @0.26 mm, 1.76 @0.63 mm,1.58 @5.57 mm |
1.8245 @0.8 mm 1.8197 @1.0 mm 1.8121 @1.4 mm |
1.6921mm - 1.3161mm |
| Specifications of Windows and Mirrors |
| Diameter |
+/-0.0, -0.1mm |
+/-0.1mm |
+/-0.0, -0.1mm |
| Thickness |
+/-0.2mm |
+/-0.2mm |
+/-0.2mm |
| Flatness |
better than λ per 25 @633nm |
better than λ/8@633nm |
better than λ per 25 @633nm |
| Parallelism |
better than 3' |
better than 30'' |
better than 3' |
| Perpendicularity |
better than 5' |
better than 5' |
better than 5' |
| Scratch-Dig |
80-50 per MIL-O-13830A |
10-5 per MIL-O-1383A |
80-50 per MIL-O-13830A |
| Wavefront Distortion |
less than l /2 per inch @1064nm |
better than l /2 per inch@1064nm |
less than l /2 per inch @1064nm |
