A team at the NUS Department of Electrical & Computer Engineering led by Dr Qiu Cheng-Wei has come out with an optical device to "engineer" ghosts. When someone claims he has seen a ghost, the phenomenon may be caused by an optical illusion happening through a wild stroke of nature. But the actual engineering of such a phenomenon is the holy grail of researchers in the field of optical illusions, electromagnetic, and radar detection—not only because of the thrill and excitement of being able to create a "ghost" but because of the implications it will have in science and applications.
Ghostly illusions could one day help disguise military aircraft for greater stealth, researchers say.
In the last eight years or so, scientists have discovered cloaking devices are possible, which can bend and twist light completely around objects, rendering them invisible. Cloaking devices that work against other kinds of waves are possible as well, such as the acoustic waves used in sonar.
However, such cloaks are usually limited to working against narrow ranges of frequencies for various types of waves. An international team of physicists instead explored devices that could potentially work against wide bands of frequencies, generating illusory ghosts as disguises.