Current Status of Terahertz Frequency Metrology and Standard at NICT

Toward the establishment of a new frequency standard in terahertz (THz) region, we have developed key technologies regarding THz frequency measurement and dissemination. Their uncertainty and instability were reached to 10
^-17
level. Contrary to the remarkable progress of these THz frequency metrology, many researches required for the THz standards are remained to be challenged.