title: Photothermal single-particle microscopy: detection of a nanolens.
abstract: Combining quantitative photothermal microscopy and light scattering microscopy as well as accurate MIE scattering calculations on single gold nanoparticles, we reveal that the mechanism of photothermal single-molecule/particle detection is quantitatively explained by a nanolensing effect. The lensing action is the result of the long-range character of the refractive index profile. It splits the focal detection volume into two regions. Our results lay the foundation for future developments and quantitative applications of single-molecule absorption microscopy.
authors.affiliation: Molecular Nanophotonics Group, Institute of Experimental Physics I, Leipzig University, 04103 Leipzig, Germany.
authors.forename: Markus
authors.initials: M
authors.lastname: Selmke
authors.forename: Marco
authors.initials: M
authors.lastname: Braun
authors.forename: Frank
authors.initials: F
authors.lastname: Cichos
mesh_terms: D000042:Absorption; D007909:Lenses; D008853:Microscopy / Q000295:instrumentation*; D036103:Nanotechnology / Q000295:instrumentation*; D013696:Temperature