Fairy Lights: Femtosecond Lasers That Can Be Touched And Felt Give Haptic Interface A New Meaning
Fairy Lights are small projections that appear to float in mid-air, and the tiny images can even be felt by a person touching the image. The free-floating plasma display could be a major step toward developing holodecks like those seen in Star Trek, where virtual projections can be felt and moved around like real-life objects.
High-speed lasers were modified to produce the unusual images. Most lasers used in similar research run with a cycle of a nanosecond — one-billionth of a second. These devices can cause a burning sensation when the beam hits flesh, making them impracticable for interactive displays. Researchers speed their lasers up a million times above normal to a femtosecond cycle. This change made the projected images safe to touch, increasing safety and practicability.
Haptic sensations, the feeling produced by pressure on the skin, are produced by the projection, giving the image a real world feel much like its science-fiction counterpart. This is the sensation we usually associate with the feel of certain materials, such as wood or various types of cloth.
Laser-induced plasma holds several advantages over other means of producing similar displays, researchers report. For one, this system does not require structures or wires that block viewing the display being projected. Also, the system does not need to suspend materials in the air to act like a 3D version of a movie screen and can be controlled to a fine degree.
"There are two methods of rendering graphics with a femtosecond laser in air: Producing holograms using spatial light modulation technology, and scanning of a laser beam by a galvano mirror," researchers wrote in a paper published by the Digital Nature Group.
Unfortunately, this technology is not likely to be available soon in living room televisions. The images produced using this latest device are only about 1/2000th of a cubic inch in size.
However, further development of the technology could develop larger versions of these images, which could be utilized for a wide range of purposes on Earth and beyond. Laser-induced plasma could be used to create new generations of augmented reality (AR) devices, as well as user interfaces capable of appearing to float in mid-air. This technology could be used to provide real-time instructions to workers carrying out tasks, even in space.
Laser-induced plasma is formed when laser beams heat gases, including those in the atmosphere, until they are hot enough to become ionized. This technology is already being developed by the military into new weapons, which could deliver blows of energy into targets from far away. Prototypes of these systems use lasers to guide electricity down a channel, headed wherever the operator deems.
A video showing the Fairy Lights in action is available on YouTube.