A semiconductor based pump‐probe system and its application to THz spectroscopy

<jats:title>Abstract</jats:title><jats:p>In this work a description of a semiconductor laser based system is presented that can be utilised in many pump‐probe experiments and in particular as the basis for a THz spectrometer. There are two methods described, one which has a stepping time delay function and the other which has a sweep time delay function. These two methods are achieved in the first case by a manipulation of the relative gain switching of two semiconductor lasers and in the second case by a gain switching of two semiconductor lasers with slightly different RF frequencies. The time delay by cross‐correlating the two gain switched laser outputs on a silicon APD via two photon absorption is demonstrated. (© 2007 WILEY‐VCH Verlag GmbH &amp; Co. KGaA, Weinheim)</jats:p>