Femtosecond laser blackening of platinum

Using a femtosecond laser processing technique, we produce the black platinum with absorptance of about 95% over a broad wavelength range from ultraviolet to infrared. From scanning electron microscopy and energy dispersive x-ray spectroscopy studies, we find that the enhanced absorption of the black metal is due to a variety of nano- and microscale surface structures. Using a unique calorimetry technique, we perform a shot-to-shot comparison study of the metal absorption change in air and vacuum. Our study shows that the blackening process for platinum is more efficient in vacuum. (C) 2008 American Institute of Physics.