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      Now you see it, now you don't

      Now you see it, now you donâ??t.

      Michigan Tech graduate student Xiaohui Wang has been working for almost three years on making things invisible.

      Itâ??s not exactly the sort of wizard-like magic youâ??re probably thinking, but itâ??s not a slight of hand eitherâ?|because behind all magic is science.

      "So, the invisibility cloak is just a device that can hide a target by enclosing the target," said Wang.

      Wang has been able to make things invisible in microwave frequencies by changing the electromagnetic properties of the cloak.

      "Traditionally, the invisibility cloak is designed by using manmade, artificial material," Wang explained. "However, the electromagnetic properties of meta-material (man-made material) are not stable. Thatâ??s why we started to design the cloak by using multilayer, ordinary materials, which do not conduct electricity."

      Itâ??s a little ironic to try to show something thatâ??s invisible, but computer models can help make sense of it. The colored part of the graphic represents the many wavelengths that are constantly surrounding us. The middle represents the material that is trying to be cloaked; in this case, an aluminum disc. The disc is surrounded by a ceramic resonator, and when you change the electromagnetic properties of that resonator, you can make the material in the middle become invisible at different frequencies.

      "Both the cloak shield, which consists of ceramics, and also the target on the inside, totally, will be invisible," Wang said.

      If you remember your high school physics class, we can only see wavelengths on the visible light spectrum. So, we canâ??t see microwaves. That means that although the object is invisible in microwave frequencies, we can still see the object with our eyes. But the goal is to make things invisible in the visible light spectrum.

      "I think it will help a lot in law enforcement, or national security, or even defense," Wang added.

      But researchers still have a ways to go before making things totally disappear.