Submillimeter wave detection with high temperature superconducting bolometers

We have fabricated and characterized a planar antenna-coupled microbolometer working at the resistive transition edge of a HTc superconducting film for use as a submillimeter wave detector. A log-periodic antenna was used to couple the incoming radiation to a YBaCuO thin film microbridge. The performance of the antenna and the bolometer response were obtained by using a 119 µm H2O laser source. Both the radiation pattern directivity and the detector responsivity were clearly improved by irradiating the antenna from the dielectric substrate side by means of a hyper-hemispherical silicon lens

Thermal Model for the Bolometric Response of YBaCuO Films on Polycrystalline YSZ at 10.6 µm Wavelength

Economical bolometers, using YBaCuO thin films sputtered on polycrystalline zirconia substrates, have been fabricated and tested at λ=10µm with a cw CO2 laser. A 2D thermal model for the bolometric response has been developed to include the film to substrate thermal boundary resistance, and take into consideration the various heat flow regimes inside the film and the substrate. This model has been found successful to predict both the amplitude and phase components of the bolometer response with respect to the modulation signal frequency. In particular, the amplitude response, which contains a succession of f-1 and f-l/2 sections separated by well-identified corner frequencies, could be quantitatively predicted in the 0.5 Hz to 100 kHz experimental frequency range