Infrared dielectric properties of low-stress silicon oxide
  Silicon oxide thin films play an important role in the realization of optical coatings and high-performance electrical circuits. Estimates of the dielectric function in the far- and mid-infrared regime are derived from the observed transmittance spectrum for a commonly employed low-stress silicon oxide formulation. The experimental, modeling, and numerical methods used to extract the dielectric function are presented. 
Giuseppe Cataldo, Edward J. Wollack, Ari D. Brown, Kevin H. Miller
physics.optics astro-ph.IM cond-mat.mtrl-sci