Responsivity enhancement of a strained silicon field-effect transistor detector at 0.3 THz using the terajet effect

We report on the enhancement of responsivity by more than one order of magnitude of a silicon-based sub-terahertz detector when a mesoscopic dielectric particle was used to localize incident radiation to a sub-wavelength volume and focus it directly onto the detector. A strained-silicon modulation field-effect transistor was used as a direct detector on an incident terahertz beam at 0.3 THz. A systematic study in which Teflon cubes were placed in front of the detector to focus the terahertz beam was performed. In this study, cubes with different sizes were investigated, and an enhancement of the responsivity up to 11 dB was observed for a cube with an edge length of 3.45 mm (or 3.45 lambda). Electromagnetic simulation results were in good agreement with the experimental ones and demonstrated that the size of the mesoscopic particle plays an important role in focalizing the electric field within an area below the diffraction limit. This approach provides an efficient, uncostly, and easy to implement method to substantially improve the responsivity and noise equivalent power of sub-terahertz detectors. (C) 2021 Optical Society of America

Automated summary

The study demonstrates that using mesoscopic dielectric particles to localize incident radiation to a sub-wavelength volume and directly focus it onto a sub-terahertz detector can enhance the responsivity by more than one order of magnitude. By placing Teflon cubes of different sizes in front of the detector, a significant increase in responsivity was observed, with enhancements of up to 11 dB.