Spectral, spatial, and survivability evaluation of a flash-dried plasma-etched nanotube spray coating

We demonstrate improved manufacturability of spectrally flat detectors for visible to mid-infrared wavelengths by characterizing a carbon nanotube spray coating compatible with lithium tantalate and other thermal sensors. Compared against previous spray coatings, it demonstrated the highest responsivity yet attained due to both higher absorptivity and thermal diffusivity, while also being matured to a commercially available product. It demonstrated spectral nonuniformity from 300 nm to 12 microm less than 1% with uncertainty (k=2) under 0.4%. The spatial nonuniformity of the assembled sensor was less than 0.5% over the central half (4 mm) of the absorber. As with previous developments employing isotropic carbon nanotube coatings, the absorber surface was sufficiently robust to withstand cleaning by compressed air blast and survived repeated vacuum cycling without measurable impact upon responsivity.