Performance of combined ⟨100⟩-⟨110⟩ ZnTe crystals in an amplified THz time-domain spectrometer

In this work we report on the performance of combined index-matched ZnTe (I I 0)-(10 0) THz emitters and detectors for reduction of etalon effects in a nonlinear crystal-based THz time-domain spectrometer, driven by an amplified femtosecond laser. We demonstrate that the application of a combined electrooptic detector crystal reduces the strength of the first etalon and the average spectral dynamic range oscillations by a factor of two. We also show that even in a simple emitter configuration the emitter-related etalon is significantly reduced due to the transient dielectric effects of carriers created by two-photon absorption in the emitter. (c) 2006 Elsevier B.V. All rights reserved.