Sensitive bolometers using high‐Tc superconducting thermometers for wavelengths 20–300 μm

Two types of sensitive high‐Tc bolometer have been fabricated on 20‐μm‐thick sapphire substrates with YBa2Cu3O7−δ thin film transition edge thermometers. The sensitivity of both devices is superior to commercially available, room temperature pyroelectric detectors. A 1×1 mm bolometer with a radiation absorber of gold black smoke has a noise equivalent power NEP=2.4×10−11 W/Hz1/2 at 10 Hz and has useful sensitivity over wavelengths 20–100 μm. A 3×3 mm bolometer with a Bi film radiation absorber has NEP=3.6×10−10 W/Hz1/2 at 10 Hz and has useful sensitivity over wavelengths 100–300 μm. Water vapor transmittance spectra were measured to demonstrate the sensitivity of both devices.