title: Differential thermal lensing in extended samples.
abstract: We present a new scheme for a pump-probe mode-mismatched thermal lensing experiment aimed at extracting the value of low-absorbing components in the presence of a high-absorbing background. The method allows for the use of large path-length samples. Changes in the background absorption of a column of ethanol of 20 cm of 1% and a pollutant concentration detection limit of 0.04 ppm are obtained when using a pump light power of 34 mW.
authors.affiliation: Centro de Física, Instituto Venezolano de Investigaciones Científicas, Caracas 1020A Apartado 21827, Venezuela. marcano@pion.ivic.ve
authors.forename: A
authors.initials: A
authors.lastname: Marcano
authors.forename: J
authors.initials: J
authors.lastname: Hung
authors.forename: L
authors.initials: L
authors.lastname: Rodríguez
authors.forename: L
authors.initials: L
authors.lastname: Borrero
mesh_terms: D004055:Differential Thermal Analysis; D000431:Ethanol / Q000032:analysis; D007834:Lasers; D012031:Refractometry; D012680:Sensitivity and Specificity; D013057:Spectrum Analysis / Q000295:instrumentation* / Q000379:methods*; D013696:Temperature; D014874:Water Pollutants, Chemical / Q000032:analysis
chemical_list: D014874:Water Pollutants, Chemical; D000431:Ethanol