Measurements of the complex refraction spectra of some selected solid specimens

Various measurement techniques that are currently being used for determination of the near millimeter wavelength optical constants of solids are compared. The comparison is achieved by each participating laboratory measuring the optical constants of seven solid specimens over as much of the spectral region between 90 and 600 GHz as their instrumentation allows. The measurement temperature is 293K. An improved understanding of the dominant random and systematic errors in each measurement technique is sought. It is concluded to be difficult to assess all of the systematic errors presented, although in some instances it is possible to identify upper limits for such errors. As these results form only one part of the measurement round robin, these limitations are not considered important.