Direct monitoring of broadband light absorbers

The final performances of manufactured thin film filters usually depend on to the monitoring strategy. Some optical monitoring systems provide transmittance measurements while others measure the reflectance. With our system, we are able to simultaneously measure both transmittance and reflectance over an extended spectral range [400 nm; 1000 nm]. This reflectance channel is necessary for direct monitoring of some kinds of filters like light absorbers. Indeed, in this case, transmittance is cancelled after the first metallic layer deposition. The optical system is also very useful for in situ characterization especially for metallic absorbing materials.