The problem with lasers is, they tend to generate just a single color or light.To get more than one hue requires actually combining more than one type of laser to produce red, green and blue. But researchers at Brown University have figured out a solution to creating small RGB lasers by using colloidal quantum dots, or CQDs. The idea of leveraging the properties of the thin film isn't new, but past attempts to use CQDs in semiconductor lasers have failed because the necessary energy tends to wind up as heat instead of light. The work around scientists found was to excite the various dot sizes with a laser then filter out original light source. Unfortunately, the solution is far from practical for use in commercial products, but it does represent a milestone in the march towards a single-material multi-wavelength laser. For more details check out the source link.