Open AccessCharacterization of absorptance homogeneity in thin-film coatings for high-power lasers by thermal lensing microscopy
Author(s) -
Facundo Zaldívar Escola,
N. Míngolo,
Sandra Martínez,
J. J. Rocca,
Carmen S. Mei
Publication year - 2019
Publication title -
applied optics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.668
H-Index - 197
eISSN - 2155-3165
pISSN - 1559-128X
DOI - 10.1364/ao.58.007233
Subject(s) - optics , materials science , laser , homogeneity (statistics) , absorptance , photothermal therapy , microscope , thin film , characterization (materials science) , microscopy , optoelectronics , lens (geology) , photothermal spectroscopy , image resolution , nanotechnology , physics , computer science , reflectivity , machine learning
A focus error method photothermal microscope was designed for the characterization of absorptance homogeneity in thin-film coatings for high-power lasers. The technique relies on the detection of the thermal lens induced by the local absorption of a light power focused laser. The detailed design of the instrument is presented. The resolution of the system is better than 0.1 ppm and allows the realization of spatial sweeps and even measurements of the evolution of absorption as a function of time with a spatial resolution of 1 μm. These capabilities allow the location of defects and their characterization.