Friend and his colleagues Nir Tessler and Graham J. Denton report the work in the Aug. 22 Nature . Like any laser, this device produces light by a process called stimulated emission. Shining light through the reflector causes the PPV to emit photons, some of which are reflected back and forth between the mirrors, in turn triggering a cascade of more photons. The photons that are not reflected but pass through the silver film have a single wavelength and are in phase, forming the coherent laser beam. The light emitted was yellow-green, but polymer laser light could, in principle, cover a range of visible wavelengths, Friend says.
Most commercial lasers emit in the red or infrared range.
The next big goal is to develop polymer lasers that can be excited by electricity rather than light. Polymers can be easily deposited over large areas. How that quality can be exploited for lasers remains to be seen, but it's useful when making large, flat LED panels such as computer screens or billboards. They will set the community looking in a new direction.