Ultimate sensitivity of a reflection interferometer with a noninverted instrumental function

Abstract

Properties of a multiple-beam interferometer with a transmission-like pattern of the fringes in reflected light are considered. A specific feature of this interferometer (a transmission-like reflection interferometer, or TRI) is an asymmetric one-sided mirror with a multilayer dielectric coating and a thin absorbing film. Characteristics of the mirrors and the interferometer as a whole are calculated as functions of the number of dielectric layers. In the calculations, the losses inside the dielectric coating, which are assumed to be concentrated in the vicinity of the layer boundaries, are taken into account. It is shown that a TRI, in terms of its sensitivity, does not differ substantially from conventional multiple-beam interferometers for the same level of technology of the dielectric coatings. The TRI version under consideration demonstrates mode self-filtration, due to which it reflects only the fraction of the incident light corresponding to the resonance of the interferometer. This allows one, in principle, to eliminate special mode cleaners and to significantly simplify the entire optical arrangement.