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Optics Express

  • Advanced materials
  • Metrology

Ultra-Wide-Range Measurements of Thin-Film Filter Optical Density Over the Visible and Near-Infrared Spectrum

Authors Michel Lequime, Simona Liukaityte, Myriam Zerrad, and Claude Amra


We present the improved structure and operating principle of a spectrophotometric mean that allows us for the recording of the transmittance of a thin-film filter over an ultra-wide range of optical densities (from 0 to 11) between 400 and 1000 nm. The operation of this apparatus is based on the combined use of a high power supercontinuum laser source, a tunable volume hologram filter, a standard monochromator and a scientific grade CCD camera. The experimentally recorded noise floor is in good accordance with the optical density values given by the theoretical approach. A demonstration of the sensitivity gain provided by this new set-up with respect to standard spectrophotometric means is performed via the characterization of various types of filters (band-pass, long-pass, short-pass, and notch).