High-density terahertz imaging systems at 2.8 THz in silicon with quantum cascade laser (QCL)-based excitation sources
Terahertz (THz) imaging has emerged as a powerful tool for a wide range of applications in security, imaging, sensing, quality control, and biomedical sensing. Current THz detector technology consists of custom devices, which are often bulky and expensive, as well as not sensitive enough to operate at room temperature. Technology for THz detection has been demonstrated in silicon, but these devices typically operate below 1 THz, can be power-intensive (>300 mW/pixel), require high-resistivity substrates, or use modifications such as silicon lenses and substrate thinning. In recent years, silicon-based THz imagers have been demonstrated in the 100-1000 GHz range, with NEP in the near 1 THz range of ~1 nW/ Hz. Beyond 1 THz there has been little work on enabling integrated imaging systems. Additionally, integrated chip-scale sources beyond 1.4 THz in silicon have never been demonstrated. In this project, we focus on the frequency range of 2.8 THz with a hybrid QCL-silicon IC solution, using a fully integrated silicon-based THz imager and a QCL laser operating at 2.8 THz.