Periodically patterned germanium surfaces modified to form superhydrophobic, IR-transmissive substrates

Various periodically patterned, infrared (IR) transmissive germanium substrates were surface modified to alter the surface wettability. Goniometric analysis showed that the surface modification rendered the substrates superhydrophobic. Following the surface modification, it was determined that the desirable IR transmission properties were maintained. Both the hydrophobicity and the IR transmission capabilities of the modified, patterned germanium substrates were shown to be significantly enhanced in comparison to a germanium substrate that underwent the same processes, but was devoid of nanostructures on its surface. The results of this work provide an opportunity for the development of enhanced utility infrared transmissive optics in wet or humid conditions.