Infrared Spectrophotometry

Infrared Spectrophotometry serves a wide variety of industries and agencies that (a) require infrared optical property information, including manufacturers of optical components, infrared detectors, and spectrophotometers, materials processing, aerospace, and defense industries, or (b) use optical measurement instrumentation, such as the chemical, pharmaceutical, food, agriculture, and remote sensing industries.

Several commercial Fourier-transform spectrometers are in service with specialized instrumentation to measure the optical properties of materials in the infrared. Measurements of the reflectance (specular and diffuse), transmittance, emittance, and refractive index of materials are being performed to customers’ requests in the wavelength range from near to middle IR. Capabilities are being continually improved for variation and control of the critical measurement parameters: temperature, angle of incidence, polarization state, and spot size (IR microscope) to satisfy customers needs.

Measurement services currently available as special tests include regular reflectance and transmittance over a range of incidence angles and over a range of temperatures from 10 K to 300 K, for the wavelength range of 1 µm to 100 µm for transmittance and 1 µm to 5 µm for reflectance. (Expansion to 25 µm is in progress.) In addition, 8 degree-hemispherical (diffuse) reflectance and transmittance can be measured from 2 µm to 18 µm. The polarimetric dependence of these properties (ellipsometry and polarimetry) can also be measured, with complete Mueller matrix information over the 2 µm to 6 µm range.

Fourier Transform Infrared Spectrophotometry (FTIS) Facility

Integrating Sphere for Specular and Diffuse Samples

Infrared Spectral Emittance of Materials

References

Testing the radiometric accuracy of Fourier transform infrared transmittance measurements,
S.G. Kaplan, L.M. Hanssen, and R.U. Datla
Appl. Opt. 36 8896-8908 (1997).