Optical Transmission and Reflectance - An optical spectrometer is used to measure specular and diffuse transmittance and reflectance. Wavelengths between 200 and 3000 nm are analyzed using a combination of tungsten and xenon light sources and Si and PbS photo-detectors. Measurement of these quantities allows other properties to be calculated including absorption coefficient, refractive index, the energy band gap of a semiconductor, and thin film thickness.

Stress Optic Coefficients - PMIC has experience in the measurement of stress or strain optic coefficients of transparent or translucent glasses or crystals. Polarized laser light passes through the material while it is subjected to compressive loads. Other optical properties can also be obtained, including retardation coefficients, indicies of refraction and bifringence parameters.

Temperature Dependence of Refractive Index (dn / dt) - PMIC has developed a unique method for measuring the temperature dependence of the index of refraction. It uses a modified Michelson interferometer and is able to simultaneously measure the CTE of the glass/crystal at the same temperature and wavelength with an accuracy of ± 0.03 x 10-6/K.

Emissivity (e) - Total hemispherical emittance of a surface is measured using a transient calorimetric technique based on a method developed at NASA Glenn Research Center (formally NASA Lewis) by Donald A. Jaworske. It is a modification of ASTM standards C835 “Total Hemispherical Emittance of Surfaces up to 1400°C” and E433 “Calorimetric Determination of Hemispherical Emittance…” The method involves heating the sample in a vacuum and allowing it to cool radiatively to a surrounding black body. Materials can be heated to 535°C (~1000°F)

Optical Properties - PMIC has additional experience in the measurement of birefringence, Kerr Constant, Verdet Constant, photometric and polarization characteristics. Spectral absorptivity, emissivity, data, etc. can be obtained with selected filters. Please contact us for your specialized optical property requirements.

Please contact us for your specialized Optical Property requirements.