Experimental Demonstration of Plasma Electron Density Diagnosis Using THz Spectral Encoding Method

THz-based plasma diagnostics is one of the newly emerged way of diagnosing various plasmas. For the practical use, however, limitation on the THz detection time should be solved. For many THz-based plasma diagnosis studies, THz time-domain spectroscopy (THz-TDS) method based on electro-optic(EO) effect has been used. Although THz-TDS is a well-established conventional method, it usually requires several minutes or more to take a THz signal. This implies that users would find it difficult to diagnose short-lived plasmas with THz-TDS. In order to circumvent this issue then, a different THz detection method should be considered. In this presentation, we present the first experimental demonstration of THz-based plasma diagnosis using spectral encoding THz detection method. Unlike the conventional plasma diagnostics, this method would allow faster plasma diagnosis based on spectral analysis of the probe laser beam and EO effect. We expect the spectral method would contribute to the study of plasma dynamics.