Terahertz time-domain spectroscopy system using compact probe heads connected with large-mode-area photonic crystal fibers

We constructed terahertz time-domain spectroscopy (THz-TDS) systems using compact probe heads, which are connected with large-mode-area photonic crystal fibers (LMA PCFs), which in turn are used for guiding ultrashort optical pulses to THz probe heads. The LMA-PCF based THz-TDS system had comparable THz radiation power and bandwidth with those obtained by a conventional THz-TDS system with free-space optical arrangement. This is because LMA PCFs are suitable for high-power delivery without introducing non-linear effects.