As a material scientist myself, I was curious about their study. So I pulled up their paper in JAP.
My first thought before reading was that the high intensity laser pulses were causing local heating such that any impurities in the solid (ie carbon) diffused onto the surface. Nope, they did an EDS scan and platinum was clearly the dominant element. There were traces of carbon but I think this was due to impurities in the microscope.
So basically what happens (my educated guess) is that the laser pulses break up the surface structure such that different phonon (http://en.wikipedia.org/wiki/Phonon) modes are excited when certain wavelengths of light are shined on the surface. Just so happens that wavelengths in the visible range are absorbed so the sample appears black. To create different colors, I guess they just found the correct amount of power and wavelength laser pulse to create the phonon mode that they need.
I don't believe they oversold their technique. Scratching won't really cause this phenomenon. Corrosion maybe, but I doubt they could achieve the same optical properties. Fragility is a legitimate concern, but I'm guessing that if they are interested in industrial applications they will do mechanical testing of the structures.
EDIT: I'd also like to add that I think it's perfectly OK for a scientist to upsell their work. We live and die by the grant system, and funding agencies are all looking for "broader impacts." I'm rather impressed that their group was able to drum up this much press.
My first thought before reading was that the high intensity laser pulses were causing local heating such that any impurities in the solid (ie carbon) diffused onto the surface. Nope, they did an EDS scan and platinum was clearly the dominant element. There were traces of carbon but I think this was due to impurities in the microscope.
So basically what happens (my educated guess) is that the laser pulses break up the surface structure such that different phonon (http://en.wikipedia.org/wiki/Phonon) modes are excited when certain wavelengths of light are shined on the surface. Just so happens that wavelengths in the visible range are absorbed so the sample appears black. To create different colors, I guess they just found the correct amount of power and wavelength laser pulse to create the phonon mode that they need.
I don't believe they oversold their technique. Scratching won't really cause this phenomenon. Corrosion maybe, but I doubt they could achieve the same optical properties. Fragility is a legitimate concern, but I'm guessing that if they are interested in industrial applications they will do mechanical testing of the structures.
EDIT: I'd also like to add that I think it's perfectly OK for a scientist to upsell their work. We live and die by the grant system, and funding agencies are all looking for "broader impacts." I'm rather impressed that their group was able to drum up this much press.