  In numerous applications of energy harvesting via transformation of light
into heat the focus recently shifted towards highly absorptive materials
featuring nanoplasmons. It is currently established that noble metals-based
absorptive plasmonic platforms deliver significant light-capturing capability
and can be viewed as super-absorbers of optical radiation. However, direct
experimental evidence of plasmon-enabled macroscopic temperature increase that
would result from these efficient absorptive properties is scarce. Here we
derive a general quantitative method of characterizing light-capturing
properties of a given heat-generating absorptive layer by macroscopic thermal
imaging. We further monitor macroscopic areas that are homogeneously heated by
several degrees with plasmon nanostructures that occupy a mere 8% of the
surface, leaving it essentially transparent and evidencing significant heat
generation capability of nanoplasmon-enabled light capture. This has a direct
bearing to thermophotovoltaics and other applications where thermal management
is crucial.
