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Published on: July 17, 2020
Absorption coefficient as a function of resistance for optical germanium at 10.6microm
Applied Optics
|February 4, 2010
Summary
Germanium single crystals show maximum transmittance at 10.6 microm when doped to 5-10 ohm-cm resistivity and n-type conductivity. This finding optimizes germanium for infrared applications.
Area of Science:
- Materials Science
- Optics
- Solid State Physics
Background:
- Germanium single crystals are utilized as infrared windows and image-forming elements.
- The purity and doping of germanium significantly influence its optical properties.
Purpose of the Study:
- To investigate the relationship between electrical resistivity and optical transmittance in germanium single crystals at 10.6 micrometers.
- To determine the optimal doping conditions for maximizing transmittance in germanium for infrared applications.
Main Methods:
- Room-temperature transmittance measurements were performed on 92 germanium single-crystal samples.
- Samples with resistivities ranging from 0.9 to 57 ohm-cm were analyzed.
- The absorption coefficient was calculated based on measured transmittances.
Main Results:
- A clear dependence of the absorption coefficient on sample resistivity was observed.
- Maximum transmittance at 10.6 micrometers was achieved for samples with a resistivity of 5-10 ohm-cm.
- N-type conductivity was associated with the highest transmittance.
Conclusions:
- Doping germanium single crystals to a specific resistivity range (5-10 ohm-cm) with n-type conductivity is crucial for optimizing transmittance at 10.6 micrometers.
- These findings provide essential data for the selection and fabrication of germanium components for infrared optical systems.
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