Biomedical subjects

Jörg Steinert

Publications and source records attributed to Jörg Steinert.

3 recordsLinked to original sources

PubMed2002

Light-scattering measurements of optical thin-film components at 157 and 193 nm.

An instrument for total backscattering and forward-scattering measurements of optical coating components at 157 and 193 nm is described. The system is operated in both vacuum and nitrogen purge gas. An excimer laser as well as a deuterium lamp can be used as a radiation source. Suppression of the background signal level to 1 part in 10(6) permits measurements even of low-scatter samples such as superpolished substrates and antireflection coatings. Results of investigations of antireflective and highly reflective multilayers and CaF2 substrates reveal scattering from surface and interface roughness as well as from the volume of the substrate material. First steps to extend the instrument for angle-resolved scatter, transmittance, and reflectance measurements are described.

Journal Article↗

PubMed2002

Optical coatings with enhanced roughness for ultrahydrophobic, low-scatter applications.

Optical coatings with enhanced roughness offer promising prospects for ultrahydrophobic transparent surfaces with controlled scatter losses. Our approach links roughness characteristics with both wetting behavior and scattering. Experiments with rough oxide layers yielded surfaces with a high water contact angle.

Journal Article↗

PubMed2002

Surface characterization techniques for determining the root-mean-square roughness and power spectral densities of optical components.

Surface topography and light scattering were measured on 15 samples ranging from those having smooth surfaces to others with ground surfaces. The measurement techniques included an atomic force microscope, mechanical and optical profilers, confocal laser scanning microscope, angle-resolved scattering, and total scattering. The samples included polished and ground fused silica, silicon carbide, sapphire, electroplated gold, and diamond-turned brass. The measurement instruments and techniques had different surface spatial wavelength band limits, so the measured roughnesses were not directly comparable. Two-dimensional power spectral density (PSD) functions were calculated from the digitized measurement data, and we obtained rms roughnesses by integrating areas under the PSD curves between fixed upper and lower band limits. In this way, roughnesses measured with different instruments and techniques could be directly compared. Although smaller differences between measurement techniques remained in the calculated roughnesses, these could be explained mostly by surface topographical features such as isolated particles that affected the instruments in different ways.

Journal Article↗