Mid-infrared time-domain spectroscopy system with carrier-envelope phase stabilization

We built a mid-infrared time-domain spectroscopy (TDS) system optimized for the 8-12 mu m spectral range based on a compact ultrafast Erbium: fiber laser that enables measurements of phase-resolved optical field transients directly in the time domain with high stability and spectral brightness. We achieved long term (>10 h) stability of the TDS signal by using a carrier-envelope-phase locking technique to reduce the timing jitter caused by environmental changes. Time domain measurements of the mid-infrared beam were achieved via electro-optic sampling in a GaSe crystal, using an ultrashort (similar to 15 fs) output of the fiber laser. Here, we present a full characterization of our TDS system including the dependence of the amplitude and pulse shape of the detected infrared waveforms on the thickness of the GaSe crystals. (C) 2013 AIP Publishing LLC.