Scientists produced incredible holographic images using nothing more than a simple inkjet printer.
The feat could drastically cut down the time and effort needed to create a "rainbow hologram," which are often used for security purposes in credit cards and currency, ITMO University reported.
To create these stunning holograms, a team of researchers developed colorless ink made of nanocrystalline titania, which they then put in a conventional printer and deposited onto a special microembossed paper. The method allowed the researchers to print custom holographic images on transparent film in a matter of minutes, current methods take days.
"The conventional way of preparing a hologram is incredibly time-consuming and consists of several stages. First of all one needs to create a master hologram, which is usually laser recorded on a thin layer of photosensitive polymer. The polymer is then dried and unexposed parts are washed out," said Aleksandr Yakovlev, first author of the study and researcher at the SCAMT laboratory. "The resulting stencil is then transferred to a metallic matrix, which eventually serves to emboss holographic microrelief on the surface of a transparent polymer film."
Once applied to the microembossed surface, the hologram is covered in a finishing varnish. This means the hologram is exclusively seen in the areas where the ink was applied.
"The peculiarity of our ink is high refractive index in all visible range of light," says project supervisor Alexander Vinogradov. "The use of nanocrystalline ink forms a layer with high refractive index, which helps preserve the rainbow holographic effect after the varnish or a polymer layer is applied on top."
The findings were published in a recent edition of the journal Advanced Functional Materials.