A fast, sensitive, room-temperature graphene nanomechanical bolometer

Bolometers are a powerful and vital means of detecting light in the IR to THz frequencies, and have been adopted for applications ranging from astronomy to thermal imaging. As uses diversify there is an increasing demand for faster, more sensitive room-temperature bolometers. To this end, graphene has generated interest because of its vanishingly small heat capacity and its intrinsic ultra-broadband absorption, properties that would allow it quickly detect low levels of light of nearly any color. Yet, it is challenging to operate a traditional electrical graphene bolometer at room temperature due to its weakly temperature-dependent resistivity and high thermal conductivity. Our method overcomes these challenges with a simple approach that employs suspended graphene as a nanomechanical bolometer, where absorbed light is detected as shift in its mechanical resonance frequency. We report on the measured sensitivity and response bandwidth of these graphene nanomechanical bolometers, which compare favorably to the state-of-the-art. Furthermore, we model the response of these devices and discuss a path to reach femtowatt sensitivity at room temperature.