Year: 2026
Type: article
Abstract: Theoretical investigations have been conducted on terahertz (THz) sensing enabled by electro-optic (EO) effect in a GaAs-based optical microcavity. The birefringence induced by THz irradiation can be detected by measuring the phase-shift signal of the infrared probe light. We clarified the substrate orientation of the microcavity suitable for THz sensing. The phase-shift signal was calculated by the extended transfer matrix method considering the multiple sidebands generated by the applied THz field. In the sub-THz frequency range, the phase-shift signal of the single cavity can be strongly enhanced with increasing quality factor. However, the signal intensity drastically decreases with increasing frequency. We demonstrate that a triple-coupled cavity, which consists of three equivalent cavity layers and four distributed Bragg reflectors, is promising to detect a specific THz field whose frequency corresponds to the spacing of three cavity modes when the sign of effective EO coefficient is reversed in the middle of structure.
Language: English
Subfield: Electrical and Electronic Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: hybrid
Estimated APC paid: $2,210
OpenAlex ID: W7204105083