We describe the optical characterisation of two silicon cold-electron bolometers each consisting of a small (32×14μm) island of degenerately doped silicon with superconducting aluminium contacts. Radiation is coupled into the silicon absorber with a twin-slot antenna designed to couple to 160-GHz radiation through a silicon lens. The first device has a highly doped silicon absorber, the second has a highly doped strained-silicon absorber. Using a novel method of cross-correlating the outputs from two parallel amplifiers, we measure noise-equivalent powers of 3.0 × 10 - 16 and 6.6×10-17WHz-1/2 for the control and strained device, respectively, when observing radiation from a 77-K source. In the case of the strained device, the noise-equivalent power is limited by the photon noise.
ASJC Scopus subject areas
- Atomic and Molecular Physics, and Optics
- Materials Science(all)
- Condensed Matter Physics