Practical considerations for the amplification of electro-optically detected THz signals

Advances in THz methods and applications require the detection of weak THz pulsed signals. One solution to this problem is to amplify weak signals using optically biased electro-optical (EO) techniques. Several different EO amplification schemes are compared. The simplest of these involves using a non-polarizing beam splitter followed by two quarter-wave plates set to small positive and negative angles, respectively. The signals are then passed through polarizers perpendicular to the polarization of the 800 nm EO detector crystal gating beam. As long as sufficient intensity is present in the gate pulse for linear photodiode detection, amplification of up to 10 times with dynamic ranges for single sweep scans of >10 4 is obtained.