Room-Temperature Fiber Tip Nanoscale Optomechanical Bolometer

Nanomechanical bolometers have proven to be well suited to the analysis of light. However, conventional wafer-based devices have limited practical applications because they require special vacuum chambers, cryogenic temperatures, bulky space optical components, and/or complex circuitry. The present work developed a nanoscale optomechanical bolometer intended for photothermal sensing using an all-optical actuation and measurement approach. The proposed bolometer is compact and has an integrated all-optical-fiber structure based on fabricating a Fabry–Perot interferometer incorporating multilayer graphene at the fiber tip and packaged in a small vacuum-sealed tube. This microscale vacuum packaging doubled the signal-to-noise ratio compared with that in air. This miniature all-fiber nanoscale optomechanical bolometer also exhibited a high resolution with photothermal sensitivities of approximately 6.23 and 6.44 kHz/μW when using the second-order mode at room temperature and 0 °C, respectively. This design could be beneficial for applications outside specialized laboratories with uses in the fields of medicine, industrial manufacturing, nanoscience, and astronomy.