The cloak is made of metamaterial, a class of artificial materials that have enhanced properties as a result of their carefully engineered structure. Fang’s team designed a two-dimensional cylindrical cloak made of 16 concentric rings of acoustic circuits structured to guide sound waves. Each ring has a different index of refraction, meaning that sound waves vary their speed from the outer rings to the inner ones.
“Basically what you are looking at is an array of cavities that are connected by channels. The sound is going to propagate inside those channels, and the cavities are designed to slow the waves down,” Fang said. “As you go further inside the rings, sound waves gain faster and faster speed.”
Since speeding up requires energy, the sound waves instead propagate around the cloak’s outer rings, guided by the channels in the circuits. The specially structured acoustic circuits actually bend the sound waves to wrap them around the outer layers of the cloak.
The researchers tested their cloak’s ability to hide a steel cylinder. They submerged the cylinder in a tank with an ultrasound source on one side and a sensor array on the other, then placed the cylinder inside the cloak and watched it disappear from their sonar.
We report an invisibility carpet cloak device, which is capable of making an object undetectable by visible light. The cloak is designed using quasi conformal mapping and is fabricated in a silicon nitride waveguide on a specially developed nanoporous silicon oxide substrate with a very low refractive index (n less than 1.25). The spatial index variation is realized by etching holes of various sizes in the nitride layer at deep subwavelength scale creating a local effective medium index. The fabricated device demonstrates wideband invisibility throughout the visible spectrum with low loss. This silicon nitride on low index substrate can also be a general scheme for implementation of transformation optical devices at visible frequencies.
Physicists have created a "hole in time" using the temporal equivalent of an invisibility cloak.
Invisibility cloaks are the result of physicists' newfound ability to distort electromagnetic fields in extreme ways. The idea is steer light around a volume of space so that anything inside this region is essentially invisible.
The effect has generated huge interest. The first invisibility cloaks worked only at microwave frequencies but in only a few years, physicists have found ways to create cloaks that work for visible light, for sound and for ocean waves. They've even designed illusion cloaks that can make one object look like another.
3D cloak is first to work in free space Aug 8, 2011
Physicists in the US claim to have created the first 3D invisibility cloak that can operate alone in free space. The cloak, based on a "plasmonic" shell, can hide a cigar-sized cylinder from microwaves – although it currently only operates for one microwave polarization.
Invisibility cloaks have been around since 2006, when a team led by David Smith at Duke University in North Carolina, US, produced a device that could guide microwaves of a very narrow frequency around an area a few centimetres in diameter. The device was based on a "metamaterial" comprising an array of resonators that altered the electrical permittivity and magnetic permeability throughout the cloak. Variations in these properties resulted in the microwaves bending round the hidden space like water around a stone, albeit only in 2D.
Pentagon Scientists Use ‘Time Hole’ to Make Events Disappear January 4, 2012 | 4:58 pm
This is the first time that scientists have succeeded in masking an event, though research teams have in recent years made remarkable strides in cloaking objects. Researchers at the University of Texas, Dallas, last year harnessed the mirage effect to make objects vanish. And in 2010, physicists at the University of St. Andrews made leaps towards using metamaterials to trick human eyes into not seeing what was right in front of them.
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Sept 17, 2013 8:24:45 GMT -8
KS Chua: I noticed someone was waiting in the dark for me on my way home tonight. I believe someone is trying to kill me. -kok SeNg chUA
Nov 17, 2013 13:35:49 GMT -8
Mark Iannicelli: The perps used an acoustic device projecting noise and pretended tobe mafia hitmen and I broke a windshield to get in jail and be safe . I was surgically implanted in New York Long Island's Nassau County jail. Perps hate for you to yell and threaten them.
Dec 13, 2013 18:04:49 GMT -8
Mark Iannicelli: I have had probes surgically implanted and V2K and nobody helps me because these lowlifes pay everyone off or use counterintelligence to disinform the people who try to help me. The perps are Meriwether from Brunswick, Georgia U.S.A. and a Joe Moody
Dec 13, 2013 18:07:32 GMT -8
Mark Iannicelli: The money from the torture and murder that these rednecks are getting here in the United States is from the Dept. of Defense's Office off Ssience and Technolgy, the Dept. of Justice Office of Science and Tecnology, the Dept. of Commerce Office of Science
Dec 13, 2013 18:10:43 GMT -8
Mark Iannicelli: BIuS
Dec 13, 2013 18:11:19 GMT -8
Mark Iannicelli: dEPT. OF cOMMERCE oFFICE OF sCIENCE AND tECHNOLOGY
Dec 13, 2013 18:12:01 GMT -8
Mark Iannicelli: Senator Shelby a Republican from Alabama has appropriated Defense spending for victims to be violated inhumanely with probes that itch , burn, shock and some have Global Positioning Systems (GPS)from companies like Positive I.D..
Dec 13, 2013 18:15:47 GMT -8
Mark Iannicelli: Di HAVE BEEN A v2k VICTIM FOR 23 YEARS AND HAVE TRAVELED THE WORLD WOTH LOWLIFES THAT GET MONEY FOR RESEARCH IN THE FORM OF GRANTS FOLLOWING ME AND TELLING PEOPLE I AM, A COMMUNIST TERRORIST WITH ALQAIDA, HOMOSEXUAL THAT MUTILATES HIMSELF , HITMAN AN MAFIA
Dec 13, 2013 18:18:07 GMT -8
Mark Iannicelli: The United States Constitution is suppose to protect us citizens but in reality it is not woth the ink that it is written in unless you are a millionaire.
Dec 13, 2013 18:19:23 GMT -8
Mark Iannicelli: I will visit you the next time I am in England if you can get the V2K out of my head.You all need to form a V2K Victim Security Task Force and post security at the hospital generators , fire alarms, inside and outside the operating and recovery rooms.
Dec 13, 2013 18:22:51 GMT -8
Mark Iannicelli: In direct conflict with christian ideology I am an advocate of assasinating the doctors and their accomplices that implant victims involuntarily with V2K because I have been tortured for 23 years.
Dec 13, 2013 18:24:23 GMT -8
Mark Iannicelli: The lowlifes when they travel abroad get help from the U.S. State Dept. with diplomatic passports and they always try to get next to the [police with an offer to train them in neighborhood watch and vehicular surveillance and pursuit.
Dec 13, 2013 18:26:34 GMT -8
Mark Iannicelli: Please check out the book The COINTELPRO PAPERS for an understanding how the F.B.I. conducts counterintelligence operations. Can you help me get the V2K out of my head?
Dec 13, 2013 18:28:11 GMT -8