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oai:docta.ucm.es:20.500.14352/439022023-08-27T17:18:42Zcom_20.500.14352_14col_20.500.14352_15

00925njm 22002777a 4500 dc Quiroga Mellado, Juan Antonio author Martínez Antón, Juan Carlos author Alonso Fernández, José author Gómez Pedrero, José Antonio author 2012-12-17 Optical absorbance within a liquid is used as a photometric probe to measure the topography of optical surfaces relative to a reference. The liquid fills the gap between the reference surface and the measuring surface. By comparing two transmission images at different wavelengths we can profile the height distribution in a simple and reliable way. The presented method handles steep surface slopes (<90 degrees) without difficulty. It adapts well to any field of view and height range (peak to valley). A height resolution in the order of the nanometer may be achieved and the height range can be tailored by adapting the concentration of water soluble dyes. It is especially appropriate for 3D profiling of transparent complex optical surfaces, like those found in micro-optic arrays and for Fresnel, aspheric or free-form lenses, which are very difficult to measure by other optical methods. We show some experimental results to validate its capabilities as a metrological tool and handling of steep surface slopes. 1094-4087 10.1364/OE.20.028631 https://hdl.handle.net/20.500.14352/43902 http://dx.doi.org/10.1364/OE.20.028631 http://www.opticsinfobase.org/ Topographic optical profilometry by absorption in liquids