|
Glass type |
Article |
DIA |
T |
Weight |
|---|
IRG 25
IRG 25 has excellent transmission in the SWIR, MWIR, & LWIR. Physical properties such as low dn/dT and low dispersion enable optical engineers to design color corrected optical systems without thermal defocusing.
Furthermore, IRG 25 can be processed by conventional grinding and polishing, single point diamond turning, or molding to support low to high volume component level fabrication.
| IR characteristics | |
|---|---|
| Composition | Ge28Sb12Se60 |
| Density | 4.66 g/cm3 |
| Thermal Expansion (20°C-100°C) | 14.0·10-6/K |
| Transition Temperature | 285°C |
| Thermal Change dn/dT (at 1 µm) | 79.2·10-6/K |
| Thermal Change dn/dT (at 5 µm) | 62.0·10-6/K |
| Thermal Change dn/dT (at 10 µm) | 61.1·10-6/K |
| Refractive Index (n at 10 µm) | 2.6030 |
| Surface quality | 60/40 polished both sides |
| Surface flatness | ≤ 5 waves P-V per surface at 632.8nm |
| Edge Worked | Saftety bevel |
| Wavelength [µm] |
Transmission (10 mm) |
Transmission (2 mm) |
Extinction [cm-1] |
|---|---|---|---|
| 1.0 | 81.6 | 96.0 | 0.203 |
| 1.5 | 95.7 | 99.1 | 0.044 |
| 2.0 | 96.2 | 99.2 | 0.039 |
| 2.5 | 96.3 | 99.2 | 0.038 |
| 3.0 | 96.5 | 99.3 | 0.036 |
| 3.5 | 97.5 | 99.5 | 0.025 |
| 4.0 | 98.0 | 99.6 | 0.020 |
| 4.5 | 95.6 | 99.1 | 0.045 |
| 5.0 | 95.6 | 99.1 | 0.045 |
| 5.5 | 98.8 | 99.8 | 0.012 |
| 6.0 | 99.0 | 99.8 | 0.010 |
| 6.5 | 98.9 | 99.8 | 0.011 |
| 7.0 | 99.1 | 99.8 | 0.009 |
| 7.5 | 98.7 | 99.7 | 0.013 |
| 8.0 | 96.1 | 99.2 | 0.040 |
| Wavelength [µm] |
Transmission (10 mm) |
Transmission (2 mm) |
Extinction [cm-1] |
|---|---|---|---|
| 8.5 | 98.1 | 99.6 | 0.019 |
| 9.0 | 97.9 | 99.6 | 0.021 |
| 9.5 | 98.0 | 99.6 | 0.020 |
| 10.0 | 98.2 | 99.6 | 0.018 |
| 10.5 | 96.9 | 99.4 | 0.031 |
| 11.0 | 93.8 | 98.7 | 0.064 |
| 11.5 | 85.0 | 96.8 | 0.163 |
| 12.0 | 60.1 | 90.3 | 0.509 |
| 12.5 | 31.1 | 79.2 | 1.167 |
| 13.0 | 31.1 | 79.2 | 1.167 |
| 13.5 | 52.0 | 87.7 | 0.654 |
| 14.0 | 69.7 | 93.0 | 0.361 |
| 14.5 | 71.8 | 93.6 | 0.332 |
| 15.0 | 63.1 | 91.2 | 0.461 |
| 15.5 | 47.2 | 86.0 | 0.752 |
| Constants of Dispersion Formulas | |
|---|---|
| B1 | 2.7574 |
| B2 | 3.0990 |
| B3 | 1.6660 |
| C1 | 0.0000 |
| C2 | 0.1596 |
| C3 | 2,045.5000 |
| D0 | 5.50·10-5 |
| E0 | 1.21·10-5 |
| λTK | 7.59·10-5 |
| Calculation Formula: Refractive index as a function of wavelength and temperature |
|---|
|
| Wavelength [µm] |
Refractive Index (@ 22 °C) |
Δn abs/ΔT [10–6/K] 22 °C |
|---|---|---|
| 0.8 | 2.7811 | 0.0 |
| 1.0 | 2.7284 | 79.2 |
| 1.5 | 2.6629 | 69.0 |
| 2.0 | 2.6423 | 65.7 |
| 3.0 | 2.6277 | 63.3 |
| 4.0 | 2.6219 | 62.4 |
| 5.0 | 2.6183 | 62.0 |
| 6.0 | 2.6154 | 61.8 |
| 7.0 | 2.6126 | 61.6 |
| 8.0 | 2.6097 | 61.4 |
| 9.0 | 2.6065 | 61.3 |
| 10.0 | 2.6030 | 61.1 |
| 11.0 | 2.5992 | 61.0 |
| 12.0 | 2.5949 | 60.8 |
| Wavelength [µm] |
Thermal Change [dn/dt] |
|---|---|
| 1 µm | 79.2·10-6/K |
| 5 µm | 62.0·10-6/K |
| 10 µm | 61.1·10-6/K |