Monochromatic optical detection is often desired. One technique to acc
omplish this is to place the detector within an optical resonator, The
authors consider the theoretical description of resonant optical dete
ction using an intrinsic semiconductor detector layer placed within a
monolithic vertical cavity. The effects of wavelength-dependent index
and absorption are included in the analysis. It is found that, unlike
passive Fabry-Perot filters, the resonant detector can have a single r
esonant peak and thus strong suppression of out-of-band light.