More luminous and energy efficient than LEDs, white lasers look to be the future in lighting and light-based wireless communication.
Honest question: what is the difference between a "white laser" and a three-color polychromatic laser array?
One third as many lasers. Not trying to be snarky, although it certainly looks that way. Simply put, a "pixel" of RGB takes up nearly three times as much room as a "pixel" of white... even if that white is tunable across the gamut. If you aren't making it tunable you've also got one third the electronics. And since we use "white" a lot more than we use RGB, being able to economically produce white in a single process is much more economical than assembling white through three chromatic devices... even if technically, they're the same.
So it's a density matter. Got it. Because from what I got from the article, it sounded like it was pretty much a single-element three color polychromatic laser. Though that's fair enough - it is true that even if my above statement is true, it is still one third of the controllers at least and that does makes things cheaper. Thanks!
It's pretty much a single-element three color polychromatic laser. HOWEVER their innovation was a manufacturing process that allows it all to be grown on one die, allowing a semiconductor fabrication process. After exhaustive research, the group finally came up with a strategy to create the required shape first, and then convert the materials into the right alloy contents to emit the blue color. Turkdogan said, "To the best of our knowledge, our unique growth strategy is the first demonstration of an interesting growth process called dual ion exchange process that enabled the needed structure."
This strategy of decoupling structural shapes and composition represents a major change of strategy and an important breakthrough that finally made it possible to grow a single piece of structure containing three segments of different semiconductors emitting all needed colors and the white lasers possible. Turkdogan said that, "this is not the case, typically, in the material growth where shapes and compositions are achieved simultaneously."
Amazing. Thanks for the further detail. This seriously sounds like it's going to do us a lot of good in many applications.
This is awesome! The potential for this is huge. And here I thought displays wouldn't get better than 4K definition. This would be a whole new ballpark of quality.
Resolution isn't particularly tricky. You also have to keep in mind that your eye can't resolve tighter than one arcsecond anyway so stupid crazy resolution doesn't buy you much. The cool thing about their approach - from a display technology standpoint - is this sentence: That means they expect to cook the shit out of the gamut you're used to: I'm "klein blue" because when I first saw an Yves Klein at the San Francisco MOMA, I got "modern art." He created a color of paint that simply can't be reproduced via offset printing or existing computer displays. International Klein Blue is beyond the gamut of our technology. Laser projectors get closer, at least. The ability to use white lasers to reproduce color means that our color reproduction increases radically.Ning's group has already shown that their structures could cover as much as 70 percent more colors than the current display industry standard.
Can anyone give a reason why you'd want to use a white laser for Li-Fi?white laser Li-Fi could be 10 to 100 times faster than LED based Li-Fi currently still under development.
Switching. The faster you can switch something, the more data you can carry over the channel. Because LEDs work by exciting a material, that material has to switch between energy states. Lasers, on the other hand, use the energy states of photons (If I understand it correctly - it's been a while). So basically the inertia you have in the physics of an LED, while orders of magnitude lower than the inertia of a filament light source, is still orders of magnitude higher than a laser.
Sorry, I meant why white lasers in particular, as opposed to e.g. red lasers. I suppose there's some extra bandwidth from having three channels, but I'm not sure this technique would actually result in a cheaper and faster system than using existing tech.
Oh, that one's even easier. White light is what we're used to. Red light is what klingons are used to. Bathe a room in white light and you're a human. Bathe it in red light and you're the Predator. The purpose is convenience and integration with our existing lives so "things that don't make your interior designer have an embolism" are de rigueur.
Good point – I was imagining something with directed beams, but looking it up the idea does seem to be just to spread light everywhere. I'm guessing anything commercial will either use light so dim you don't notice it, or either infrared or ultraviolet, though – I suppose if it was just integrated into light bulbs that would work, as long as you want the light on (although it might still be cheaper to use a red laser with green and blue LEDs to make the overall lighting white).
I have no experience with LiFi, or any visible-light data transfer. I do have experience with infrared ALS. It works really well if: - you have a herkin' emitter - that you're facing - in a room without sunlight this thing is about 200 high-output infrared LEDs blasting their hearts out. You can't really use them in single-channel mode because you want redundancy so you either have two or you run it in dual-channel mode. It's good for about 4-5000 square feet (contrary to their assurances of more) which means it'll hit one medium-sized lecture hall. And it will work only if the receiver is literally under your chin, where it's basking in the light of this thing. Wanna transmit data for tablets or laptops? Well, now we have to move it overhead. Which means we need a lot more of them. basically they'll be in the same place as light fixtures. And they're going to have to be on a network... the same as light fixtures. And they'll be pumping out more energy than your light fixtures because your light fixtures are also putting out a crapton of noise in that wavelength unless you filter it off, which gets really inefficient for infrared and completely implausible for red. So in the end, you have two sets of light fixtures, one for you and one for your computer, and the one for your computer uses more energy and costs more. That's why nobody's really fucked around with it much until it becomes part of the light fixtures, I reckon. PWM the shit out of the lights and you won't even notice the flicker and if you have the bandwidth, you can even put multiple channels on the same carrier. Just in my perusal of "white LED switching speed" it seems like 100MHz is a good number... which is not fast. Lasers? Terahertz.