A Japanese team has emerged from their smoke filled labs with a Star Trek style 3D volumetric display that you can actually touch by zapping the air until it glows using a laser.
The hologram has a million and one uses but one which is appropriate this week is to create a set of Christmas lights which cannot be destroyed by the cat. So far 3D holograms have used a high-power laser which heats a spot in the air until it ionises and glows with a bright blue light. This would be cat proof but would probably ionise the cat, or any small child which touches them.
The Japanese boffins worked out that if you used a really fast laser, a femtosecond laser, that heats a small spot to a high temperature but only for a very short time. This is much safer because the total energy involved is smaller. You can touch sparks without getting burned.
So far the “holograms” are small very small – Christmas tree light sized.
The system could be scaled up and be used in entertainment or in augmented reality systems. If you are thinking of the sort of “hard light” projector that created holograms in Star Trek.
Researchers at the Arizona State University (ASU) said they’ve made a breakthrough and have created a laser that beams white light.
To produce a white laser beam, the full visible colour spectrum is required, and the ASU boffins have proven that semiconductor lasers are capable of doing just that.
The scientists made a nanosheet with three parallel segments with each supporting laser in one of three colours but can tune colours from the RGB display.
The research means that lasers are now potentially a mainstream light source and will replace light emitting diodes (LEDs) by providing brighter and more energy efficient devices.
The ASU scientists believe that the white lasers could provide a combination illimination and communication system – called Li-Fi. This is likely to be over 10 times faster than current wi-fi systems and Li-Fi based on lasers may be between 10 to 100 times faster than LED based Li-Fi.
Doctoral student Fan Gan said: “Our goal is to achieve a single semiconductor piece capable of laser operation in the three fundamental lasing colours. The piece should be small enough so that people can perceive only one overall mixed colour instead of three different colours.”
One obstacle is that the semiconductor based white layer needs to be driven by a battery, and that’s not yet achievable.