This is the VOA Special English Technology Report.

A hologram is a three-dimensional image -- an image that appears to have height, width and depth.

More than 30 years ago, Princess Leia gave her famous holographic plea for help in the original "Star Wars" movie. Since then, holograms have become bigger, better and more widely used.

Now, researchers have developed a holographic telepresence system. Traditional telepresence systems are used in video conferencing. They present two-dimensional images.

But the new system might be able to send a moving 3-D image of a person over great distances -- and show it in close to real time.

Nasser Peyghambarian is the lead researcher for the project at the University of Arizona in Tucson. He says holographic technology can make people appear in places where they have never been.

Nasser Peyghambarian: "People can see you just the way you are as if you've been there."

With the new system, the image is refreshed so often that it seems to look like a person's natural movement. An important part of the system is a screen that can refresh the holographic image every two seconds. The screen is made from a special photorefractive material.

In experiments, the researchers placed 16 cameras in a half-circle. They took pictures of people from different positions. Then the researchers sent the images to a different place over the Internet.

Lasers at the other end received the pictures and produced holographs on the screen. Mr. Peyghambarian says the new material permits the images to be continually written, erased and replaced.

Nasser Peyghambarian: "Every image that you want to show only takes two seconds to write it. And therefore the next image comes in after that. And this capability allows this system to be used for, for example, telepresence -- that an object in one location now can be [virtually] transferred or can be shown in another location in 3-D."

He says the more cameras and the more pictures that are used, the more realistic the holographic image appears.

The researchers imagine their technology being used for things like 3-D maps and movies requiring no special glasses. Doctors could use it for telemedicine. But the researchers say their holographic telepresence system is still years away from completion.

A report on the system appeared in the journal Nature.

And that's the VOA Special English Technology Report, written by June Simms with Jessica Berman. You can learn about other new uses for 3-D technology at voaspecialenglish.com. You can also join us on Facebook and Twitter at VOA Learning English. We'll talk more about telepresence systems next week. I'm Mario Ritter.

（来源：VOA 编辑：陈丹妮）