Carbon-based coatings for thermal detectors: laser damage and thermal efficiency

The laser damage threshold and absorption efficiency of a variety of carbon based thermal coatings for laser power and energy measurements have been investigated. Carbon based paint, carbon fibers, as well as single wall carbon nanotubes (SWCNTs) and multiwalled carbon nanotubes (MWCNTs), were applied to a water cooled copper substrate. The heating of the water was measured to determine power absorbed by the sample during laser exposure. Before and after exposure to 10.6 µm laser radiation, optical and electron microscopy as well as Raman spectroscopy were employed to evaluate the coating topology and composition. These early measurement results demonstrate that a MWCNT coating has a damage threshold of approximately 1686 W/cm 2 , which is four times as large as that measured for SWCNTs and fifteen times greater than that of carbon based paint.