The invention of the electric light-bulb was a watershed event in human history. Since then, we have been using electric sources of light in our homes, offices, roads, and cars. However, electric lights are often bulky, produce a lot of heat, and do not last long. Over the last 40 years or so, tremendous progress has been made in solid-state devices, which include semiconductor-based microprocessor chips, sensors and Light-Emitting-Diodes (LEDs).
Scientists have long been working on boosting the light output of the LEDs, so that they can work as replacements for the more traditional incandescent light-bulbs. Finally, their work is slowly beginning to bear fruit :):).

Let there be (Solid-State) Light! (Courtesy: PhysOrg)In an article published in the journal Science, the researchers E. Fred Schubert and Jong Kyu Kim of Rensselaer Polytechnic Institute describe research currently under way to transform lighting into smart lighting, with benefits expected in such diverse fields as medicine, transportation, communications, imaging, and agriculture.
The applications include the ability to control basic light properties — including spectral power distribution, polarization, and color temperature — will allow smart light sources to adjust to specific environments and requirements and to undertake entirely new functions that are not possible with incandescent or fluorescent lighting.
There will be a lot of power savings: solid-state sources potentially could cut in half the 22 percent of electricity now consumed by lighting. Traffic lights using LEDs, for example, use only one-tenth the power of signals using incandescent lamps.
Other applications include automatic modification of light frequency, modulation and intensity to match the human circadian rhythm, light-based communication between cars on the road so as to minimize chances of collisions, better optical transmission lines, and improved resolution in microscopes.