Angular Airy function: a model of Fabry-Perot etalons illuminated by arbitrary beams

Fabry-Perot (FP) etalons are used as filters and sensors in a range of optical systems. The reflected transmitted fields associated with an FP etalon have traditionally been predicted by the Airy function, which assumes plane wave illumination. are, however, often illuminated non-collimated beams, rendering function invalid. To address this limitation, we describe angular calculates for arbitrary illumination using spectrum decomposition. Combined realistic models experimental beams detection optics, show that can accurately predict wavelength resolved intensity measurements. Based on fundamental operating principle is angular-spectral filter. interpretation explain asymmetry, broadening visibility reduction seen measurements from high Q-factor focused Gaussian beams.