title: Comparison of BaTiO3 optical novelty filter and photothermal lensing configurations in photothermal experiments.
abstract: Photorefractive BaTIO3 is used as an optical novelty filter to highlight the high spatial frequency components of the photothermal signal. A real-time phase grating recorded in BaTIO3 acts as a matched rejection spatial filter for the probe laser. This reduces the stationary background from the optical signals thereby increasing signal contrast ratios. Rejection of the monotonous stationary signal provides a powerful means of improving the photothermal signal. This paper describes the construction of this novel apparatus and the experiments performed in order to compare its performance with photothermal lensing results. A theory that explains photothermal signal filtering with BaTIO3 as an adaptive spatial frequency filter is presented. Results comparing the optical signals obtained in a photothermal lensing experiments and those obtained in the BaTIO3 optical novelty filter experiments are presented. The optical novelty filter signals demonstrate a remarkable improvement in the signal contrasts for moderate photothermal-induced phase shifts.
authors.affiliation: Department of Chemistry and Biochemistry, Utah State University, Logan 84322-0300.
authors.forename: S D
authors.initials: SD
authors.lastname: Kalaskar
authors.forename: S E
authors.initials: SE
authors.lastname: Bialkowski
mesh_terms: D001464:Barium; D017609:Barium Compounds; D007909:Lenses; D008433:Mathematics; D010783:Photometry; D014025:Titanium
chemical_list: D017609:Barium Compounds; C024547:barium titanate(IV); D001464:Barium; D014025:Titanium