There is a plethora of ongoing research aimed at uncovering a method that would enable the full, and infallible invisibility of an object. It seems most hopes for future success are pinned on the use of metamaterials.
Metamaterials are artificial materials made-up of different elements, which have been arranged into specific patterns. What’s interesting is that metamaterials don’t exhibit the properties of the elements which make them up. Instead parameters like shape, size and arrangement determine their properties; meaning that they interact with light in a peculiar way.
Due to their unique properties, light ‘bends’ around metamaterials rather than being reflected off them, as is the case with normal objects. If no light waves bounce off an object then no light waves enter our eyes telling us there is something there. Hey presto, invisibility.
It’s not just the metamaterial itself which would remain unseen; any object placed inside the metamaterial would also become undetectable.