Detection of ultrathin biological films using vacuum ultraviolet spectroscopic ellipsometry

Spectroscopic ellipsometry (SE) is a non-contact and a non-destructive optical technique used in characterization of thin films. It is widely used to determine optical constants, thickness in multilayer stacks and microstructure (voids, alloy fraction, or mixed phase composition). This paper reports on a systematic investigation of the optical properties of two different kinds of silane compounds: 3-aminopropyltriethoxysilane (APTES) and 3-glycidoxypropyltriethoxy-silane (GPS) as well as for immunoglobulin G (IgG) attached to these modified samples using vacuum ultraviolet spectroscopic ellipsometry (VUV-SE). VUV-SE is a newly developed technique and used to evaluate the strength and energy of the interband electronic excitations/transitions in these biofilms. The shorter wavelengths of VUV-SE increase sensitivity for detection of extremely thin adsorbed films at an interface (\u3c10 nm) and accurately determine optical properties of biological interactions/ moieties on the surface. A Cauchy dispersion model was used to determine layer thicknesses in multilayer stacks and adsorption was accounted by including Gaussian shaped oscillators in the optical model. No measurable optical anisotropy is found for these films. The dielectric properties of the adsorbed films are reported in the 0.73–9.43 eV optical range

Detection of ultrathin biological films using vacuum ultraviolet spectroscopic ellipsometry

Spectroscopic ellipsometry (SE) is a non-contact and a non-destructive optical technique used in characterization of thin films. It is widely used to determine optical constants, thickness in multilayer stacks and microstructure (voids, alloy fraction, or mixed phase composition). This paper reports on a systematic investigation of the optical properties of two different kinds of silane compounds: 3-aminopropyltriethoxysilane (APTES) and 3-glycidoxypropyltriethoxy-silane (GPS) as well as for immunoglobulin G (IgG) attached to these modified samples using vacuum ultraviolet spectroscopic ellipsometry (VUV-SE). VUV-SE is a newly developed technique and used to evaluate the strength and energy of the interband electronic excitations/transitions in these biofilms. The shorter wavelengths of VUV-SE increase sensitivity for detection of extremely thin adsorbed films at an interface (\u3c10 nm) and accurately determine optical properties of biological interactions/ moieties on the surface. A Cauchy dispersion model was used to determine layer thicknesses in multilayer stacks and adsorption was accounted by including Gaussian shaped oscillators in the optical model. No measurable optical anisotropy is found for these films. The dielectric properties of the adsorbed films are reported in the 0.73–9.43 eV optical range

Giant Optical Anisotropy in 2D Metal-Organic Chalcogenates

Optical anisotropy is a fundamental attribute of some crystalline materials and is quantified via birefringence. A birefringent crystal not only gives rise to asymmetrical light propagation but also attenuation along two distinct polarizations, a phenomenon called linear dichroism (LD). Two-dimensional (2D) layered materials with high in- and out-of-plane anisotropy have garnered interest in this regard. Mithrene, a 2D metal-organic chalcogenate (MOCHA) compound, exhibits strong excitonic resonances due to its naturally occurring multi-quantum well (MQW) structure and in-plane anisotropic response in the blue wavelength (~400-500 nm) regime. The MQW structure and the large refractive indices of mithrene allow the hybridization of the excitons with photons to form self-hybridized exciton-polaritons in mithrene crystals with appropriate thicknesses. Here, we report the giant birefringence (~1.01) and tunable in-plane anisotropic response of mithrene, which stem from its low symmetry crystal structure and unique excitonic properties. We show that the LD in mithrene can be tuned by leveraging the anisotropic exciton-polariton formation via the cavity coupling effect exhibiting giant in-plane LD (~77.1%) at room temperature. Our results indicate that mithrene is an ideal polaritonic birefringent material for polarization-sensitive nanophotonic applications in the short wavelength regime

INTEGRATED MID-INFRARED, FAR INFRARED AND TERAHERTZ OPTICAL HALL EFFECT (OHE) INSTRUMENT, AND METHOD OF USE

System Stage, and Optical Hall Effect (OHE) system method for evaluating such as free charge carrier effective mass, concentration, mobility and free charge carrier type in a (51) Int. Ci. sample utilizing a permanent magnet at room temperature

Reflective Infrared Ellipsometry Of Plastic Films

High resolution reflective ellipsometry is used to study freely suspended plastic films. We determine room temperature optical constants in the infrared for a variety of plastics using ellipsometry. The films are typically 6 to 100 μm thick and measurements are performed from near infrared to long wave-IR. The setup includes modeling software to fit the ellipsometric data to a generalized oscillator model. The films studied include acrylics, fluoropolymers, and variations of polyethylene, polystyrene, and polyvinyl chloride (PVC) among others. We are able to determine in-plane and out-of-plane optical constants. Transmission spectra from FTIR measurements are plotted and compared with ellipsometry results. © Springer Science+Business Media, LLC 2006

Progress in spectroscopic ellipsometry: Applications from vacuum ultraviolet to infrared

Spectroscopic ellipsometry (SE) is a noncontact and nondestructive optical technique for thin film characterization. In the past 10 yr, it has migrated from the research laboratory into the semiconductor, data storage, display, communication, and optical coating industries. The wide acceptance of SE is a result of its flexibility to measure most material types: dielectrics, semiconductors, metals, superconductors, polymers, biological coatings, and even multilayers of these materials. Measurement of anisotropic materials has also made huge strides in recent years. Traditional SE measurements cover the ultraviolet, visible, and near infrared wavelengths. This spectral range is now acquired within seconds with high accuracy due to innovative optical configurations and charge coupled device detection. In addition, commercial SE has expanded into both the vacuum ultraviolet (VUV) and midinfrared (IR). This wide spectral coverage was achieved by utilizing new optical elements and detection systems, along with UV or Fourier transform IR light sources. Modern instrumentation is now available with unprecedented flexibility promoting a new range of possible applications. For example, the VUV spectral region is capable of characterizing lithographic materials for 157 nm photolithography. The VUV also provides increased sensitivity for thin layers (e.g., gate oxides or self-assembled monolayers) and allows investigation of high-energy electronic transitions. The infrared spectral region contains information about semiconductor doping concentration, phonon absorption, and molecular bond vibrational absorptions. In this work, we review the latest progress in SE wavelength coverage. Areas of significant application in both research and industrial fields will be surveyed, with emphasis on wavelength-specific information content