Examination of Mid-Infrared Photon Detection by Hot Electron Bolometer With Twin Slot Antenna

As a high-speed and sensitive mid-infrared (MIR) photon detector, we developed a MIR superconducting hot electron bolometer (MIR-HEB). The MIR-HEB consists of a twin-slot MIR-wavelength antenna and a small Nb/NbN superconducting strip located at the antenna's feeding point. To prevent the HEB from latching, a parallel shunt resistor was added. For detector evaluation, a continuous-wave quantum cascade laser with a wavelength of 4.57 μm was used as the source of MIR light. A constant bias current was applied near the HEB critical current during the detector operation. Upon illumination with MIR light, numerous voltage pulses with a width of approximately 4 ns were observed. Furthermore, it was demonstrated that the pulse count rates were nearly proportional to the incident power over a two-order magnitude range. We conclude that MIR-HEB achieved MIR photon detection based on this result. Also confirmed were the polarization dependences attributed to the antenna's operation.