Optical Homogeneity refers to the degree of refractive index can (Δn) along the optical path within a given blank. The homogeneity of an optical element is of great importance since the variations in refractive index distort the wavefront of light transmitted through the optical component..
Synthetic Fused Silica - Optical Homogeneity Table 1 |
|||||
---|---|---|---|---|---|
Fused Silica Grade |
Index homogeneity Class2 |
Maximum Index Variation (@ 632.8 Nanometers) |
|||
Dynasil® |
Corning HPFS® 79801 |
(X 10-6) |
|||
Optical Grade |
UV Grade |
X= |
|||
Selected Fused Silica (Selected for lowest inclusions, bubbles, strain, and striae) |
410X |
110X |
|||
1 |
A |
1.0 |
|||
B |
1.5 |
||||
2 |
C |
2.0 |
|||
3 |
D |
3.0 |
|||
4 |
E |
4.0 |
|||
5 |
F |
5.0 |
|||
6 |
- |
6.0 |
|||
7 |
- |
7.0 |
|||
0 |
G |
Not Specified |
|||
Standard Fused Silica (For inclusions, bubbles, strain and striae specifications.) |
400X |
100X |
|||
1 |
A |
1.0 |
|||
B |
1.5 |
||||
2 |
C |
2.0 |
|||
3 |
D |
3.0 |
|||
4 |
E |
4.0 |
|||
5 |
F |
5.0 |
|||
6 |
- |
6.0 |
|||
7 |
- |
7.0 |
|||
0 |
G |
Not Specified |
|||
Commercial Fused Silica | 5000 |
Not Specified |
|||
6000 |
Not Specified |
||||
1Minimum external transmittance at 185 nanometers 18 80% for UV grades when measured through a 0.394"" (10mm) polished, uncoated sample. 2Index Homogeneity:
|
Synthetic Fused Silica - Inclusions and Bubbles Table 2 |
||||||
---|---|---|---|---|---|---|
Fused Silica Grade 4,5 |
Inclusion Class3 |
Maximum Blank Size (Dynasil Material) |
Inclusions and Bubbles |
|||
Dynasil® |
Corning HPFS® 79803 |
Diameter or Diagonal X Thickness mm (inch) |
Total Inclusion Cross - Section mm2 / 100cm3 (Upper Limit in in2 / in3) |
Maximum Diameter of Largest Inclusion mm (inch) |
||
Optical Grade |
UV Grade3 |
|||||
Selected Fused Silica |
410X |
110X |
0 |
152 X 51 (6 X 2) |
0.03 (7.62 X 10-6) |
0.10 (.004) |
1 |
305 X 51 (12 X 2) |
0.10 (2.54 X 10-5) |
0.25 (.011) |
|||
Standard Fused Silica |
400X |
100X |
2 |
203 x 51 (8 x 2) |
0.25 (6.35 x 10-5) |
0.50 (.020) |
3 |
356 x 51 (14 x 2) |
0.50 (1.27 x 10-4) |
0.76 (.030) |
|||
4 |
559 x 76 (22 x 3) |
1.00 (2.54 x 10-4) |
1.00 (.040) |
|||
Commercial Fused Silica |
5000 |
5 |
559 x 102 (22 x 4) |
2.00 (5.08 x 10-4) |
1.27 (.050) |
|
6000 |
559 x 102 (22 x 4) |
4.00 (1.02 x 10-3) |
2.03 (.080) |
|||
3 Inclusions, bubbles and seeds smaller than 0.10mm (0.004"") in diameter are disregarded in this specification. 4 All Selected and Standard Grade material meets the striae requirements of ISO 10110-4 Class 2/5 (No Visiblie Striae) in the thickness direction. 5 All Selected and Standard Grade material meets or exceeds the stress birefringence requirements of ISO 10110-2 Class 0/5 |