Terahertz sources

Terahertz spectroscopy

Figure 1 - Analogy between the Hertz experiment and the first THz experiments based on photocommutators. Emission and detection principles are detailed in the inserts.

Figure 2 - Surface emission: process involving charge displacement (surface straightening not shown)

Figure 3 - Zinc tellurium (ZnTe) crystals (a). DAST crystal and its molecular structure (b)

Figure 4 - THz generation by frequency difference

Figure 5 - Schematic diagram of four-wave mixing

Figure 6 - Schematic layout of OPO-THz components

Figure 7 - THz photomixing spectrometer

Figure 8 - THz-TDS spectrometer set-up

Figure 9 - THz signal transmitted through a sapphire plate

Figure 10 - THz spectrum of mannitol

Figure 11 - Flame spectroscopy schematic diagram

Figure 12 - Schematic diagram of optical pump spectroscopy – THz probe (POST)

Figure 13 - Results of the variation of the transient dielectric function for different doping levels in a semiconductor (here InP).

Figure 14 - Diagram of the arrival times of the various pulses used in a POST experiment