Patent ID: 10451651

Abstract:
A tunnel current control apparatus includes a light source, a branching unit, a chopper, an optical path difference adjustment unit, a polarizer, a terahertz wave generation element, a CEP adjustment unit, a terahertz wave detection element, a quarter-wave plate, a polarization separation element, photodetectors, a differential amplifier, a lock-in amplifier, a current measurement unit, a processing unit, mirrors, and off-axis parabolic mirrors. The CEP adjustment unit can arbitrarily adjust a CEP of a terahertz wave pulse. The processing unit obtains a conversion filter used for conversion from an electric field waveform of a far field of the terahertz wave pulse to an electric field waveform of a near field based on a tunnel current measured by the current measurement unit and a correlation detected by the terahertz wave detection element.