Laser-Aided Automated Removal of Anti-Reflective Coatings From Germanium Substrates

High-purity germanium (Ge) is manufactured into infrared (IR) lenses for most DoD night sight IR optics, thermal imaging systems, and IR tracking systems in combat vehicles. A recent report by Umicore (ADA’s partner for this proposed project) identifies several current and future needs for Ge, showing growing needs in the middle of severe shortfall. These applications are essential for tracking ground targets and heat-seeking missiles and conducting nighttime counterinsurgency operations. Dependence of metallic Ge supplies (~85% or more of demand) from non-US suppliers, along with increased procurement costs and growing significant shortfalls, as well as increased production delays (for DoD applications) inflicted by the commercial sector’s high Ge demands, has necessitated the development of agile, automated, cost-effective and reliable Ge recycling technologies. Specifically, traditional grinding based coating removal from DoD systems such as IR reflective optics leads to significant delays, costs (associated with highly labor-intensive, difficult-to-scale processes) with significant Ge losses during pre-recycling. To address this need, ADA proposes the development and installation of an automated laser surfacing system (ALSS), which will be designed to ensure fast, cost-effective coating removal (such as thorium fluoride, carbon black) from Ge substrates with virtually no loss of Ge and minimal surface destruction.