Page 68 - Chalcogenide Glasses for Infrared Optics

R R
Calculated Calculated R R R R
from from Calculated Calculated Calculated Calculated
Literature Covalent for S for Se for Si-Te for Ge-Te
Element Values Radii Glasses Glasses Glasses Glasses
Si 9.45 10.1 12.5 9.6
Ge 11.35 13.4 9.7 8.3 9.9
P 10.6 ∗ 8.8 3.3 9.1 13.8 15.0
As 11.6 † 12.5 11.0 12.2 11.6 12.2
S 7.95 7.85 8.4
Se 11.51 11.55 11.55
Te 18.55 18.21 17.05 17.8

∗ From P-Se4 glass.
† From As-Se4 glass.

TABLE 2.6 Atomic Refraction Values for IVA, VA, and VIA Elements When Used in
Chalcogenide Glasses

Servo No. Composition N at 5 µm N Calculated % Error
1 As Se 2.79 2.62 –6.0
38.7 61.3
2 As Se 2.65 2.59 –2.3
27.5 72.5
3 As Se Te 2.88 2.90 +0.7
40 35 25
4 As Se Te 3.07 3.06 –0.3
40 25 35
5 As Se Te 3.08 3.11 +1.0
30 30 40
6 As Se Te 2.74 2.80 +2.2
20 60 20
7 As Se Te 2.90 2.71 –6.5
35 45 20
9 As Se Te 2.77 2.75 –0.7
45 45 10
10 As Se Te 2.91 2.93 +0.7
25 45 30
11 As Se Te 2.76 2.71 –1.8
30 60 10
12 As Se Te 2.73 2.89 +5.9
10 60 30
13 As Se Te 2.84 2.94 +3.5
20 50 30
14 As Se Te 2.65 2.68 +1.1
20 70 10
16 As Se Te 2.83 2.72 –3.9
35 55 10
17 As Se Te 2.82 2.76 –2.0
30 55 15
18 As Se Te 2.80 2.81 +0.4
25 55 20
19 As Se Te 2.64 2.84 +7.5
20 55 25
20 As Se Te 2.78 2.92 +5.0
15 55 30
Average ±2.9%
TABLE 2.7 Measured and Calculated Refractive Index Values for Servo As-Se-Te
Glasses 5

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