ABSTRACT

A miniature neon indicator lamp costing about 50 cents was found to be an excellent room temperature THz radiation detector. It is also known as a Glow Discharge Detector (GDD). A down conversion method using the GDD for 300 GHz radiation is presented in this work. Previous results with the GDD at 10 GHz showed 20 times better sensitivity in down conversion detection compared to direct detection. Preliminary results at 300 GHz also showed better sensitivities in down conversion compared to direct detection.

The experimental set-up is composed of two THz sources based on RF multipliers. We present a novel experimental setup for down-conversion using two THz sources with low power radiation. The first is a 300 GHz source and the second is 300 GHz+Df source, where Df stands for the frequency difference between the two sources whose value in this experiment is about 1000 Hz. Using a beam splitter configuration we combine the two beams and direct them to the GDD. Since the GDD is a square law detector, the difference frequency, Df, is obtained and detected in the electronics circuits. In this configuration better sensitivities were achieved as compared to direct detection. We anticipate better detection performance for higher values of Df due to lower detector noise at higher frequencies.