The Nanotechnology speaks again. Now we can create a device that can make objects or humans invisible. This principle is old already but it couldn't be created until now. The background image is taken from the object that we want to hide and it is shown in front, and so we cannot see the object, this becoming invisible.

The device still has a major difficulty: it produce invisibility only on a single wave length instead of many, but in the future this flaw might be eliminated. The device can make an object invisible on a length of 632.8 nanometers which correspond to red color for example. It may be done this on other colors but not simultaneous, this may result that we can see that object partial transparent.

Even for objects with a single color, the existent light might change its color or intensity and the color of the object is changing too and so will be seen.

The invisibility has three conditions:
- the object must not reflect the light (must not contain glass, metal, etc);
- must exist a space between the object and background so the device can retrieve the image from there;
- the object must not create any shadow because of the light will create a shadow which will appear in opposite part;

Another problem is that the object when creates a shadow, the background image will be with a shadow on it and the device must modify that image.

The biggest problem is how to make the refraction index above 1. This index gives the quantity of light reflected by an object, being the same phenomenon with that when the light change its direction when goes from one medium to another as example from air to water or reverse.