Category Archives: Light

Cold Incandescent Light Bulbs?

Just when you thought incandescent bulbs were going out, they’ve been “reinvented” to be even more efficient than LEDs!

Normally Incandescent bulbs are about 5-10% efficient as most of the energy is converted to wasted heat and this age-old problem has finally been solved.

We’re literally talking about recycling light in a two step process.

The key is to create a two-stage process, the researchers report. The first stage involves a conventional heated metal filament, with all its attendant losses. But instead of allowing the waste heat to dissipate in the form of infrared radiation, secondary structures surrounding the filament capture this radiation and reflect it back to the filament to be re-absorbed and re-emitted as visible light. These structures, a form of photonic crystal, are made of Earth-abundant elements and can be made using conventional material-deposition technology.

That second step makes a dramatic difference in how efficiently the system converts electricity into light. One quantity that characterizes a lighting source is the so-called luminous efficiency, which takes into account the response of the human eye. Whereas the luminous efficiency of conventional incandescent lights is between 2 and 3 percent, that of fluorescents (including CFLs) is between 7 and 15 percent, and that of most commercial LEDs between 5 and 20 percent, the new two-stage incandescents could reach efficiencies as high as 40 percent, the team says.

The first proof-of-concept units made by the team do not yet reach that level, achieving about 6.6 percent efficiency. But even that preliminary result matches the efficiency of some of today’s CFLs and LEDs, they point out. And it is already a threefold improvement over the efficiency of today’s incandescents.

The team refers to their approach as “light recycling,” says Ilic, since their material takes in the unwanted, useless wavelengths of energy and converts them into the visible light wavelengths that are desired. “It recycles the energy that would otherwise be wasted,” says Soljačić.

The rest of the article available here: http://news.mit.edu/2016/nanophotonic-incandescent-light-bulbs-0111 mentions that the crystal is created with readily available natural ingredients so cost will probably not be an issue if they actually get these out to the public.

Longitudinal Light Wave?

An interesting new development allows light to be directed in a unique way.

Using a gold-plated silicon array, light can be made to move at 90 degrees from where it came from and the strange thing is that the light moves in a STRAIGHT LINE instead of in a sinusoidal pattern. That prevents interference between two different phases of light.

This is not a claim that the light is transmitting in some sort of longitudinal way, but it sure sounds like it – especially when it was reported that there was no time delay between the transmission of light from one point to the other. Longitudinal transmission would mean that energy is not lost at 90 degrees from the direction that the light is moving as opposed to a transverse “sinusoidal pattern”.

Another interesting thing is that the original article posted by PBS did state that the light was transmitted instantaneously to the other side instantaneously. Shortly thereafter, they were asked to correct the article so that the laws of physics were not violated.

A previous version of this article mistakenly reported that light hitting the chip was transmitted to the other side instantaneously. That would violate the laws of physics, of course. We regret the error.

Go here for the full article: http://www.pbs.org/wgbh/nova/next/tech/new-gold-plated-silicon-array-can-control-light/