TeraHertz Spectroscopy

The most efficient way to produce TeraHertz pump pulses in a tabletop setup is the “tilted wavefront generation” [1].
Starting from a Ti:Sa amplified laser system at 1 kHz of repetition rate (about 1 W of power), we obtained THz pulses with more than 100 nJ of energy corresponding to a fluence higher than 10 μJ/cm2 (Fig. 1). With this setup we are studying the optical properties of GaAs just below the band gap as we expect a huge variation due to the Dynamical Franz-Keldysh effect (DFKE) [2]. The probe light at 900 nm was filtered from the super-continuum spectrum (Fig. 2).
This setup shows good resolution (ΔR/R ≳ 10-4) and will be soon upgraded with an array detection apparatus in order to perform one-shot broadband white-light probe experiments.


Fig.1Fig.1


Fig.2



[1] Hebling et al., J. Opt. Soc. Am. B 25 B6 (2008)
[2] Jauho and Johnsen, PRL 76 4576 (1996)
Last Updated on Tuesday, 17 April 2012 15:52