TY - JOUR A1 - Beckmann, Jörg A1 - Marchetti, B. A1 - von Chrzanowski, Lars S. A1 - Ritter, E. A1 - Puskar, L. A1 - Aziz, E. F. A1 - Schade, U. T1 - Optical constants of harmful and highly energetic liquids for application to THz screening systems N2 - The far-infrared (IR) optical constants of a set of hazardous and flammable liquids have been obtained by means of spectroscopic ellipsometry in attenuated total reflection configuration over a broad spectral range. Such liquids recently became of considerable concern for transportation security measures worldwide. Their optical identification at check-in gates can only become possible if the characteristic spectra are already known. The refractive indices and the extinction coefficients reported here contribute to a spectroscopic data base in the far-IR and terahertz (THz) spectral regions and may support modeling the performance of THz screening systems on liquids for airports and other security sensitive areas. Examples of several container material/liquid systems are discussed. From the measured optical constants typical THz waveforms are calculated and discussed. KW - liquids material characterization KW - Ellipsometry KW - FT-IR spectroscopy KW - THz time-domain spectroscopy (THz-TDS) PY - 2016 DO - https://doi.org/10.1109/TTHZ.2016.2547319 SN - 2156-342X VL - 2016 / Vol. PP IS - 99 SP - 1 EP - 12 PB - IEEE - Inst. Electrical Electronics Engineers Inc CY - New York, NY, USA AN - OPUS4-36366 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schade, U. A1 - Dawei, C. A1 - Puskar, L. A1 - Ritter, E. A1 - Beckmann, Jörg T1 - Removal of Etalon Features in the Far-Infrared–Terahertz Transmittance Spectra of Thin Polymer Films N2 - Etalon features in infrared spectra of stratified samples, their influence on the interpretation and methods to circumvent their presence in infrared spectra have been in discussion for decades. This paper focuses on the application of a method originally developed to remove interference fringes in the mid-infrared spectra for far-infrared Fourier transform spectroscopy on thin polymer films. We show that the total transmittance-reflectance technique, commonly used for mid-infrared, also works successfully in the far infrared spectral range where other approaches fail. Experimental spectra obtained by such technique are supported by model calculations and reveal the possibility and limits to obtain almost undisturbed far-infrared spectra which are suitable to determine low energy vibrations of ionomer salts under certain sample conditions. KW - Far-infrared spectroscopy KW - Absorption KW - Etalon feature KW - Total transmittance reflectance PY - 2020 DO - https://doi.org/10.1177/0003702820922295 VL - 74 IS - 12 SP - 1530 EP - 1539 PB - Sage journals AN - OPUS4-51367 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schade, U. T1 - Etalon Effects in THz Film Measurements N2 - Etalon effects in THz transmittance spectra, either taken in time-domain or frequency-domain, often hamper or even hinder the interpretation of film properties. In this paper we discuss the transferability and applicability of spectroscopic methods usually employed in the near and mid infrared spectral range and exemplarily present the application field. T2 - 45. International Confercene on infrared, milimeter and terahertz waves CY - Online meeting DA - 08.11.2020 KW - Far-infrared spectroscopy KW - Etalon Effects PY - 2020 UR - https://live-irmmwthz.pantheonsite.io/technical-program AN - OPUS4-51652 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Beckmann, Jörg A1 - Puskar, L. A1 - Ritter, E. A1 - Schade, U. T1 - Novel Technique for On-Line Monitoring of the Curing Process of Fiber Reinforced Polymer Composites N2 - A specially developed experimental set up has been integrated into a commercially available FT IR Spectrometer to study the curing of Epoxy Systems. MIR and FIR spectra measured during the curing process at different temperatures of an epoxy system will be presented in dependency of the curing time. The experiments and the selected set up are discussed to demonstrate its potential for future monitoring and ageing control applications during a manufacturing process of polymer composites. T2 - 45. International conference on infrared, millimeter, and terahertz waves CY - Online meeting DA - 08.11.2020 KW - Far-infrared spectroscopy KW - Online Curing Monitoring PY - 2021 SN - 978-1-7281-6620-9 DO - https://doi.org/10.1109/irmmw-thz46771.2020.9370646 SP - 1 PB - IEEE AN - OPUS4-53059 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schade, U. A1 - Puskar, L. A1 - Golnak, R. A1 - Veber, A. A1 - Beckmann, Jörg T1 - Infrared Attenuate Total Reflection Cell with a Functionalized Surface N2 - ATR cell utilizing chips from silicon wafers is discussed. The cell can be used for wet-chemical analysis on functionalized surfaces. Here, silicon chips are exemplarily "functionalized" by silica layers to provide a hydrophilic or hydrophobic ATR surface in-situ. T2 - 48th International Conference on Infrared, Millimeter, and Terahertz Waves (IRMMW-THz) CY - Montreal, Quebec, Canada DA - 17.09.2023 KW - THz radiation KW - ATR KW - FTIR PY - 2023 DO - https://doi.org/10.1109/IRMMW-THz57677.2023.10298918 SP - 1 PB - IEEE CY - New York, NY AN - OPUS4-59326 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schade, U. A1 - Puskar, L. A1 - Ritter, E. A1 - Beckmann, Jörg T1 - Etalon effects in THz film measurements N2 - Etalon effects in THz transmittance spectra, either taken in time- domain or frequency-domain, often hamper or even hinder the interpretation of film properties. In this paper we discuss the transferability and applicability of spectroscopic methods typically employed in the near and mid infrared spectral range to eliminate the fringes in the transmittance spectra in the THz spectral range. T2 - 2020 45th International Conference on Infrared, Millimeter, and Terahertz Waves (IRMMW-THz) CY - Buffalo, NY, USA DA - 08.11.2020 KW - THz radiation KW - Total transmittance reflection technique KW - Etalon effects PY - 2020 SN - 978-1-7281-6620-9 DO - https://doi.org/10.1109/IRMMW-THz46771.2020.9370451 SN - 2162-2035 SN - 2162-2027 SP - 1 PB - IEEE CY - Buffalo, NY AN - OPUS4-56943 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schade, U. T1 - Etalon effects in THz film measurements N2 - Etalon features in transmittance spectra of films arise due to the coherent superposition of waves caused by reflections multiple times at the inner film boundaries. The fringe maxima occur at i𝜆 = 2nd cos 𝜑 with i - being an integer, 𝜆 - the wavelength, d - the film thickness, 𝜑 - the angle of incidence in respect to the film normal and n - the refractive index of the film. It is obvious that such features can hinder the interpretation of absorption bands when fringe amplitude and period are in the same range as the expected bands. This poster discusses the suitability of two optical methods for the THz spectral range applied to Fourier Transform Spectroscopy. T2 - 2020 45th International Conference on Infrared, Millimeter, and Terahertz Waves (IRMMW-THz) CY - Buffalo, NY, USA DA - 08.11.2020 KW - THz radiation KW - Total transmittance reflection technique PY - 2020 AN - OPUS4-56945 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schade, U. T1 - Estimation of THz waveforms for material characterization of stratified objects N2 - The poster discusses theoretically and exemplarily the influence of the materials and experimentally selected situation on the shape and size deformation of a detected pulse signal previously reflected on a three layer sheet. T2 - 41st International Conference on Infrared, Millimeter, and Terahertz Waves (IRMMW-THz 2016) CY - Copenhagen, Denmark DA - 25.09.2016 KW - THz spectroscopy KW - Pulse reflection KW - Pulse shape analysis KW - Optical layer model PY - 2016 AN - OPUS4-37639 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schade, U. A1 - Ritter, E. A1 - Aziz, E. F. A1 - Puskar, L. A1 - Beckmann, Jörg T1 - Spectroscopic ellipsometry on liquids in the far infrared N2 - The far infrared refractive indices and the extinction coefficients of liquids can be obtained by means of spectroscopic ellipsometry in attenuated total reflection configuration. Such optical constants will contribute to a spectroscopic data base in the far infrared and terahertz spectral regions. The experimental implementation and the calibration procedure of the method are described in detail. The temperature dependency of the optical constants for water over a broad spectral range is exemplarily presented. T2 - 42nd International Conference on Infrared, Millimeter and THz Waves CY - Cancun, Mexico DA - 27.08.2017 KW - Ellipsometry KW - Far Infrared KW - ATR KW - Attenuated total reflection KW - Calibration KW - Extinction coefficients KW - Refractive index measurement KW - Spectroscopic ellipsometry KW - Far infrared refractive index KW - Terahertz spectral region KW - Optical constant KW - Attenuated total reflection configuration KW - Liquid extinction coefficient KW - Optical refraction KW - Optical variables control KW - Optical reflection KW - Liquids KW - Optical films KW - Optical polarization KW - Optical variables measurement PY - 2017 UR - http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=8066931&isnumber=8066832 DO - https://doi.org/10.1109/IRMMW-THz.2017.8066931 SN - 2162-2035 SP - MD.1.5-1 EP - MD.1.5-2 PB - IEEE CY - Danvers AN - OPUS4-42028 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schade, U. A1 - Ritter, E. A1 - Bawagan, A.D.O. A1 - Beckmann, Jörg A1 - Aziz, E. F. T1 - Far-infrared absorption measurements on thin polymer films N2 - Interference fringes in the far-infrared spectra of thin films are the result of the coherent adding up of waves and can influence the spectral interpretation by concealing smaller features. A number of methods have been developed in order to eliminate such oscillating features from the transmittance spectrum. The paper critically evaluates the total transmission-reflection technique and applies the method to quantify the spectra of different polymer films. T2 - IRMMW-THz 2014 - 39th International conference on infrared, millimeter, and terahertz waves CY - Tucson, Arizona, USA DA - 14.09.2014 KW - Far-infrared spectra KW - Thin films KW - Total transmission reflection technique KW - Infrared spectroscopy KW - Light absorption KW - Light reflection KW - Polymer films KW - Far-infrared absorption measurements KW - Thin polymer films KW - Interference fringes KW - Spectral interpretation KW - Transmittance spectrum KW - Oscillating features KW - Total transmission-reflection technique KW - Interference KW - Absorption KW - Finite impulse response filters KW - Optical films KW - Optical reflection PY - 2014 UR - http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=6956145&isnumber=6955975 SN - 978-1-4799-3877-3 DO - https://doi.org/10.1109/IRMMW-THz.2014.6956145 IS - IEEE Catalog No.: CFP14IMM-ART SP - 1 EP - 2 AN - OPUS4-32700 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -