title: Intrinsic linewidth of the plasmonic resonance in a micrometric metal mesh.
abstract: The intrinsic linewidth and angular dispersion of Surface Plasmon Polariton resonance of a micrometric metal mesh have been measured with a collimated mid-infrared beam, provided by an External Cavity tunable Quantum Cascade Laser. We show that the use of a collimated beam yields an observed resonance linewidth γ = 12 cm(-1) at the resonance frequency ν0 = 1658 cm(-1), better by an order of magnitude than with a non-collimated beam. The extremely narrow plasmon resonance attained by our mesh is then exploited to reconstruct, by varying the QCL angle of incidence θ, the angular intensity distribution f(θ) of a globar at the focal plane of a conventional imaging setup. We thus show that f(θ) is better reproduced by a Gaussian distribution than by a uniform one, in agreement with ray-tracing simulation.
authors.affiliation: Center for Life NanoScience@Sapienza, Istituto Italiano di Tecnologia, Viale Regina Elena 291, 00185 Rome, Italy.
authors.forename: L
authors.initials: L
authors.lastname: Baldassarre
authors.forename: M
authors.initials: M
authors.lastname: Ortolani
authors.forename: A
authors.initials: A
authors.lastname: Nucara
authors.forename: P
authors.initials: P
authors.lastname: Maselli
authors.forename: A
authors.initials: A
authors.lastname: Di Gaspare
authors.forename: V
authors.initials: V
authors.lastname: Giliberti
authors.forename: P
authors.initials: P
authors.lastname: Calvani