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Abstract
The University of Southern Indiana (USI) is partnering with the Jet Propulsion Laboratory (JPL) to design, build, and test a new amplifier at 2700 GHz. No amplifiers currently exist anywhere near this frequency. The USI student research team designed an optical testbed to measure amplification from this new type of amplifier built from a quantum cascade metasurface (QCMS). The QCMS is a specially designed semiconductor material that resonates photons producing amplification of a monochromatic source. The main design component of the optical testbed was the design and fabrication of an elliptical mirror block. The reason an elliptical mirror was chosen is that it allows for the source, amplifier, and detector to be positioned at the foci of the mirror and for the source to be reflected into the amplifier, and then the amplified light beam reflected onto a detector.
The team has taken two trips to JPL. In first trip during the summer of 2023, they used a frequency multiplier chain (FMC) that operates at ~2500 GHz as the source and using the QCMS amplifier they successfully measured ~2 dB. Building on this result, JPL and USI decided to try a different source called a quantum cascade laser (QCL) that operates similarly to the QCMS amplifier. The advantage of the QCL is that it has more initial power than the FMC, but a different radiation pattern. Based on this new radiation pattern, the team designed a second mirror block that was tested in spring 2024. They also characterized the frequency and radiation pattern of the QCL. This paper will discuss the design and fabrication process, the measurement setup, and results of both the QCMS amplifier from summer 2023 and QCL from spring 2024.