“…The phase factor is of an infrared beam by a factor g(ff) in a round trip (i.e., 1 b + ib' 2rridff, where the physical thickness of the laafter internal reflections at both the front and back surfaces, mella is d, and the (free-space) wave number is o. Ordinarily, and two traversals of the thickness d). The factor g(ff) is the transmittance would simply by obtained from primarily intended to model variations in sample thickness across the optical beam, which arise from surface roughness, T= p = 16(n2 + k2) e 2b' (2) larger-scale nonflatness of the two surfaces, or overall non-[(n + 1)2 + k]2 1 -r21 r23e2'132 parallelism (wedge) of the surfaces. However, refractiveindex fluctuations across the beam would produce variations implicitly assuming that the degree of spectral and spatial in optical thickness that were completely equivalent in their coherence between the incident beam and all its internal reeffect of reducing g (cr).…”