Measurements of the optical constants of metals at submillimeter wavelengths are sparse. We have used a nonresonant cavity to measure, at room temperature, the angle averaged absorptance spectra P(ω) of aluminum, molybdenum, tantalum, titanium, tungsten, and iron in the 30–300-cm-1 wavenumber region. The real part of the normalized surface impedance spectrum, z(ω) = r(ω) + ix(ω), was determined from P(ω). Measurements were also made on iron from 400 to 4000 cm-1 using standard reflectance techniques. The r(ω) spectrum was combined with previous measurements by others at higher frequencies and Kramers-Kronig analyses of the resultant combined r(ω) spectra provided ε(ω) = ε1(ω) + iε2(ω) and N(ω) = n(ω) + ik(ω).
© 1988 Optical Society of America
Mark A. Ordal, Robert J. Bell, Ralph W. Alexander, Jr., Lawrence A. Newquist, and Marvin R. Querry, "Optical properties of Al, Fe, Ti, Ta, W, and Mo at submillimeter wavelengths," Appl. Opt. 27, 1203-1209 (1988)