Optical response of a titanium-based cold-electron bolometer

Abstract

We present experimental results on the testing of cold-electron bolometer (CEB) detectors comprised of a thin Ti film absorber and two SIN junctions integrated with a planar antenna. The CEB performance was tested in a He3 sorption cryostat HELIOX-AC-V at bath temperatures of 280–305 mK. The optical response was measured using the hot/cold load method by flipping a Cu reflector opposite a blackbody surface inside a 3 K shield and using a thermal source with variable temperature. In the first experiment, the detector chip was mounted in an optical sample-holder whose aperture was switched towards or away from a blackbody source changing the incident radiation temperature from 3 K to 270 mK. As a result, we measured the optical response to a 3 K/270 mK radiation temperature change. The measured voltage response value for the detector integrated in a double-dipole antenna was ΔVout = 120 μV. This corresponds to a noise equivalent power of NEP = Vn/(dV/dP) = 3.5 × 10−17 W Hz−1/2, where dV/dP is the voltage to power response obtained from the incoming power estimation based on the Planck formula.