'Plasmonic Nanolaser': Tiny, Ultrafast Laser Created Using Silver Nanoparticles

Researchers at Aalto University, Finland , say they are the first to develop a 'plasmonic nanolaser' that operates at visible light frequencies and uses so-called 'dark lattice modes.' The laser works at length scales 1,000 times smaller than the thickness of a human hair, and the results open new prospects for on-chip coherent light sources that are extremely small and ultrafast. The laser operation is based on silver nanoparticles arranged in a periodic array. In contrast to traditional lasers, where the feedback of the lasing signal is provided by mirrors, the 'nanolaser' uses radiative coupling between silver nanoparticles. These 100-nanometer-sized particles act as tiny antennas. To produce high-intensity laser light, the interparticle distance was matched with the lasing wavelength so that all particles of the array radiate in unison. Organic fluorescent molecules were used to provide the input energy necessary for lasing.