A novel terahertz time-domain spectroscopic endoscope based on a single photoconductive antenna chip

Abstract: The common terahertz time-domain spectroscopy (THz-TDS) based on photoconductive antenna (PCA) needs two separate PCA chips. One PCA works as an emitter, and the other works as a receiver. For a reflection-type measurement, the technique called 'attenuated total reflection' usually is needed to enhance the reflection sensitivity. These make the system bulk and complicated for the reflection-type measurement. In this paper, we propose a novel THz-TDS endoscope that is specifically designed for reflection-type measurement. This THz-TDS endoscope is benefited from an integrated photoconductive antenna (we call it iPCA), which integrates the emitter and receiver on a single antenna chip. Therefore, the dimension of the endoscope can be shrunk as much as possible for practical usage. We present the design and working principle of this THz-TDS endoscope in details. It may open a promising way for the THz-TDS application in biomedical fields.