Terahertz radiation detection with a cantilever-based photoacoustic sensor

We report the photoacoustic (PA) response in the terahertz (THz) range by employing a detection process actuated with a silicon cantilever pressure sensor and a carbon-based radiation absorber. The detection relies on the mechanical response of the cantilever, when the volume of the carrier gas inside the PA cell expands with the heat produced by the radiation absorber. The detector interferometrically monitors the movement of the cantilever sensor to generate the PA signal. We selected the absorber material with the highest THz responsivity for detailed studies at 1.4 THz (214 pm wavelength). The observed responsivities of two different radiation absorbers are nearly the same at 1.4 THz and agree within 10% with responsivity values at 0.633 pm wavelength. The results demonstrate the potential of covering with a single PA detector a broad spectral range with approximately constant responsivity, large dynamic range, and high damage threshold. Published by Optica Publishing Group under the terms of the Creative Commons Attribution 4.0 License.

Automated summary

We reported the photoacoustic response in the terahertz range using a silicon cantilever pressure sensor and a carbon-based radiation absorber. The mechanical response of the cantilever acted as the detector, monitoring the expansion of the carrier gas due to the heat produced by the radiation absorber. Detailed studies were conducted using the absorber material with the highest responsivity at 1.4 THz, demonstrating the potential of a single PA detector to cover a broad spectral range with consistent responsivity, large dynamic range, and high damage threshold.