There is one major issue, however, as majority of the metamaterial invisibility cloaks out there will only be able to function with a tiny range of frequencies of light. When used at the wrong frequency, the cloak could be actually self-defeating, ending up as more visible even so. Needless to say, the scientists are currently working to improve on that situation, which means that a true invisible beam has yet to be achieved. I suppose that in due time, their efforts will be able to pay off, and chances are the military would want to dip their fingers in it as soon as possible. Imagine cloaking an entire platoon of tanks that roll up to the enemy’s borders without them knowing. Now, if only there was a way to cloak sound…