title: Collective lasing from a linear array of dielectric microspheres with gain.
abstract: We experimentally study the optical emission behavior of a linear array of dielectric microspheres with gain. The microspheres are randomly arranged and well-separated, and can only couple via radiative modes. We observe resolution-limited, ultra-narrowband modes in the longitudinal emission, which constitutes collective lasing from the entire array, inferred from the observation of a lasing threshold. The lasing modes show wavelength selectivity, wherein the lasing probability is large only in specific frequency bands while being inhibited at other wavelengths, a behavior which is independent of the degree of configurational randomness. Analysis of the frequency bands indicates the participation of Fabry-Perot resonances of the individual microspheres in the collective emission.
authors.affiliation: Nano-Optics and Mesoscopic Optics Laboratory, Tata Institute of Fundamental Research, 1, Homi Bhabha Road, Mumbai, India.
authors.forename: Anjani Kumar
authors.initials: AK
authors.lastname: Tiwari
authors.forename: Balu
authors.initials: B
authors.lastname: Chandra
authors.forename: Ravitej
authors.initials: R
authors.lastname: Uppu
authors.forename: Sushil
authors.initials: S
authors.lastname: Mujumdar
mesh_terms: D003198:Computer Simulation; D017076:Computer-Aided Design; D004867:Equipment Design; D019544:Equipment Failure Analysis; D007368:Interferometry / Q000295:instrumentation*; D007834:Lasers; D008863:Microspheres; D008962:Models, Theoretical; D012542:Scattering, Radiation