When we hear the word Laser, first thing comes to our mind is, colorful lights emerged from different tiny points. By mixing the colors in different ratios, we get new types of color. Till now, one laser can radiate a specific color. Recently, a researcher team has made a single material that can produce several different wavelengths and therefore different colors of laser light emerge.
With the combination of 3 single colored lasers Red, Green and Blue (RGB), it’s possible to replicate the whole visible light spectrum. Using the created single material which is capable of producing several wavelengths of laser light, Brown University Physicist Cuong Dang and his team have successfully completed the experiment. Cuong Dang made a full RGB laser. To make this RGB laser, he used Colloidal Quantum Dots (CQDs) and thin films that can produce light via quantum excitations. The size of the quantum dot determines what color of the light it will emits. It is possible by overlaying many small patches of CQDs on surface.
Quantum dots are mini wafers of semi conducting material. Their minute size means that quantum excitations are easily controllable. This means the light emitted by a quantum dot depends on the material it is made of as well as the physical size of the dot. Larger dots emit longer wavelengths than the smaller dots. For example: a redder light and smaller sized dots makes more violet shade.
Producing RGB lasers on a single semiconductor is a lengthy process, where each color has to be made of a different material, then patched together. The idea of leveraging the properties of the thin film isn’t new. In the past, CQDs in semiconductor lasers failed. Researchers found that the energy input required to begin light emission created heat rather than laser light. So the fact is, the solution is far from practical for use in commercial products.
No doubt, it has represent a milestone in the march towards a single material multi-wavelength laser. For more, you can visit here.
Source : Arstechnica