Real-time, terahertz impulse radar based on asynchronous optical sampling

We propose real-time THz impulse radar based on time-of-flight measurement of a pulsed THz wave. Combined use of the THz impulse radar with asynchronous optical sampling technique can achieve a real-time distance measurement of a moving and/or distant object because it requires no mechanical stages for time delay. The achieved precision of the THz impulse radar was 550 mum to an object at a distance of 1 m.