title: Toward subdiffraction transmission microscopy of diffuse materials with silver nanoparticle white-light beacons.
abstract: We demonstrate high resolution transmission microscopy in a conventional two-photon wide-field fluorescence microscope by exploiting nonlinear white light generation from clusters of silver nanoparticles placed beneath the specimen. Surface-enhanced two-photon luminescence occurs at nanoparticle hot spots in the form of spectrally broad, spatially confined light which can be exploited to determine the transmission properties of a sample placed on the silver nanoparticles. We demonstrate the versatility of the technique by revealing individual crystalline domains formed in the diffuse biological photonic crystals of the scales of a beetle. We can identify submicron changes between photonic crystal facets as well as the occurrence of stacked domains invisible to surface-sensitive methods. Control over wavelength, polarization, and pulse shape promises selective addressing of hot spots in nanoparticle assemblies for motionless spatial scanning of the transmission properties with subdiffraction resolution.
authors.affiliation: Department of Physics and Department of Chemistry, University of Utah, Salt Lake City, Utah 84112, USA.
authors.forename: Debansu
authors.initials: D
authors.lastname: Chaudhuri
authors.forename: Jeremy W
authors.initials: JW
authors.lastname: Galusha
authors.forename: Manfred J
authors.initials: MJ
authors.lastname: Walter
authors.forename: Nicholas J
authors.initials: NJ
authors.lastname: Borys
authors.forename: Michael H
authors.initials: MH
authors.lastname: Bartl
authors.forename: John M
authors.initials: JM
authors.lastname: Lupton
mesh_terms: D000818:Animals; D003460:Crystallization; D004058:Diffusion; D008027:Light; D053768:Metal Nanoparticles / Q000737:chemistry*; D008855:Microscopy, Electron, Scanning / Q000379:methods; D046529:Microscopy, Electron, Transmission / Q000379:methods; D008856:Microscopy, Fluorescence / Q000379:methods; D036103:Nanotechnology / Q000379:methods; D017785:Photons; D012834:Silver / Q000737:chemistry*; D048889:Weevils
chemical_list: D012834:Silver