Effective detection of weak terahertz pulses in electro-optic sampling at kilohertz repetition rate

The standard terahertz (THz) detection mechanism known as electro-optic sampling can be improved in sensitivity by biasing the polarization of the sampling field. In this work, we show theoretically and experimentally how weak signals can be amplified without inducing distortions. Our study identifies the influence of THz field strength, the polarization quality, and biasing amplitude on signal amplification and distortion. Here we present a distortion- free amplification of a factor of 28 while at the same time reducing the measurement time significantly