Infrared dipole-coupled bolometer response on a hemispherical silicon immersion lens

Response of an infrared (λ = 10.6 μm) dipole antenna-coupled bolometer fabricated at the center of the flat side of a hemispherical silicon immersion lens is presented. Predicted and measured antenna patterns as well as the ratio of power from the lens-side to the air-side are provided as a function of illumination F/#. The power-division ratio, Φlens/Φair, is shown to be given by the square root of the lens dielectric constant, ϵSi1/2=3.4, for F/# larger than F/2 whereas as F/# decreases to F/1 the ratio increases to 5 due to off-axis features in the radiation pattern.