title: Absorption coefficient imaging by near-field scanning optical microscopy in bacteria.
abstract: We present a method for obtaining a position-dependent absorption coefficient from near-field scanning optical transmission microscopy. We show that the optical transmission intensity can be combined with the topography, resulting into an absorption coefficient that simplifies the analysis of different materials within a sample. The method is tested with the dye rhodamine 6G, and we show some analysis in biological samples such as bacteria KIebsiella pneumoniae and Pseudomonas aeruginosa. The calculated absorption coefficient images show important details of the bacteria, in particular for P. aeruginosa, in which membrane vesicles are clearly seen.
authors.affiliation: Laboratório de Nano-Espectroscopia Optica, Universidade São Francisco, Av. São Francisco de Assis 218, 12916-900 Bragança Paulista SP, Brazil. adepaula@nanolab.usf.br
authors.forename: Ana M
authors.initials: AM
authors.lastname: de Paula
authors.forename: Claudilene R
authors.initials: CR
authors.lastname: Chaves
authors.forename: Haroldo B
authors.initials: HB
authors.lastname: Silva
authors.forename: Gerald
authors.initials: G
authors.lastname: Weber
mesh_terms: D001419:Bacteria / Q000648:ultrastructure*; D007711:Klebsiella pneumoniae / Q000648:ultrastructure; D008853:Microscopy; D055095:Optics and Photonics; D011550:Pseudomonas aeruginosa / Q000648:ultrastructure