ISSN 0253-2778

CN 34-1054/N

open

Detailed characteristic images of fingerprints developed by NaGdF4:Yb,Er-Fe3O4 nanomaterials under a 980 nm infrared laser on metal substrates. (a) Complete fingerprint without IR light, (b) dustpan, (c) bifurcation, (d) ridge ends, (e) bridges and (f) islands.