Attenuated total reflection (ATR) has long relied on a familiar trio—prism, metal film, and substrate—to unlock insights into material properties. In this work, we demonstrate the possibility and limitations of a prismless ATR system that utilizes the relative permittivity of air in place of a prism, followed by a plasmonic test material, which is in turn followed by a novel material characterized by low real relative permittivity and near-zero imaginary relative permittivity. We show that such measurements are possible in the visible IR and UV frequency ranges. In addition, we illustrate the advantages of prismless ATR.
Levy et al. (Sat,) studied this question.