Ge - Germanium
American Photonics optical grade germanium is used mainly in instruments and imaging systems in the wavelength range of 2 to 12µm. It can be made into windows, lenses and partial reflectors. APC germanium is non-hygroscopic, non-toxic, has good strength and thermal conductivity, and excellent surface hardness.
In CO2 laser applications, germanium is used as a 99% partial reflecting rear mirror. This allows a portion of the laser to transmit for built in power meters. Germanium has also found many applications in the military sector.
American Photonics offers these raw materials:
Mechanical Properties |
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Density |
(@25°C) |
5.323g/cm3 |
Knoop Hardness |
(@20°C) |
780 kg/mm2 |
Rupture Modulus |
(@20°C) |
13,000 psi |
Young's Modulus |
(@20°C) |
14.9 X 106 psi |
Poisson's ratio |
(@20°C) |
0.28 |
Thermal Properties |
||
Coefficient of Thermal Expansion |
(@20°C) |
5.7 X 10-6/°C |
Thermal Conductivity |
(@20°C) |
0.60 W/cm/°C |
Specific Heat |
0.31 J/g/°C |
|
Optical Properties |
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Index of refraction inhomogeneity (∆ n/n) |
||
(ppm @ 10.6µm) |
<29 |
|
Thermo-optic coefficient, dn/dT |
||
(K-1 @ 10.6µm) |
40 X 10-1 |
|
Bulk Absorption Coefficient |
||
(cm-1 @ 2.5µm) |
0.01 |
|
(cm-1 @ 7.0µm) |
0.017 |
|
(cm-1 @ 9.0µm) |
0.025 |
|
(cm-1 @ 5.25µm) |
0.035 |
|
Refractive Index |
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Wavelength (µm) |
Index |
Wavelength (µm) |
Index |
Wavelength( µm) |
Index |
Wavelength (µm) |
Index |
2.2 |
4.0879 |
5.0 |
4.0160 |
7.8 |
4.0061 |
10.6 |
4.0028 |
2.4 |
4.0732 |
5.2 |
4.0149 |
8.0 |
4.0057 |
10.8 |
4.0026 |
2.6 |
4.0599 |
5.4 |
4.0139 |
8.2 |
4.0053 |
11.0 |
4.0025 |
2.8 |
4.0523 |
5.6 |
4.0128 |
8.4 |
4.0049 |
11.2 |
4.0024 |
3.0 |
4.0451 |
5.8 |
4.0118 |
8.6 |
4.0044 |
11.4 |
4.0023 |
3.2 |
4.0399 |
6.0 |
4.0107 |
8.8 |
4.0042 |
11.6 |
4.0023 |
3.4 |
4.0311 |
6.2 |
4.0097 |
9.0 |
4.0040 |
11.8 |
4.0022 |
3.6 |
4.0289 |
6.4 |
4.0092 |
9.2 |
4.0038 |
12.0 |
4.0021 |
3.8 |
4.0267 |
6.6 |
4.0087 |
9.4 |
4.0036 |
12.2 |
4.0020 |
4.0 |
4.0245 |
6.8 |
4.0083 |
9.6 |
4.0034 |
12.4 |
4.0020 |
4.2 |
4.0223 |
7.0 |
4.0079 |
9.8 |
4.0033 |
12.6 |
4.0019 |
4.4 |
4.0205 |
7.2 |
4.0074 |
10.0 |
4.0031 |
12.8 |
4.0019 |
4.6 |
4.0189 |
7.4 |
4.0070 |
10.2 |
4.0030 |
13.0 |
4.0018 |
4.8 |
4.0172 |
7.6 |
4.0066 |
10.4 |
4.0029 |
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