Background

Here you can read about various topics constituting the platform for our research.

The mid-IR spectrum: a challenge for ultrafast laser technology

A major drive behind mid-IR few-cycle pulses is exactly research in ultra-fast molecular dynamics, e.g., the de-phasing of vibrations in liquid water and phase transitions in correlated matter. Ultimately the grand challenge is control, e.g., over the vibrational transitions of chemical bonds, which could lead to the discovery of new properties of matter. In particular the focus is on the important hydrogen bonds, whose vibrational "fingerprints" lie in the 2.5-3.5 μm wavelength region, and the carbon doublet and triplets in the 4-7 μm range. From 7-20 μm, i.e. at the end of the mid-IR and the beginning of the far-IR, is the so-called "fingerprint region" where all organic compounds have a unique spectral absorption pattern due to single-bond bending modes. In order to excite any of these vibrations in a coherent manner energetic mid-IR pulses must be used with a temporal duration shorter than the vibrational period of the chemical bonds. This can only be realized when the pulses are few-cycle duration.

A current obstacle is that today’s ultrafast laser technology is almost exclusively located in the near-IR regime, and while parametric amplification is standard it always comes at a price of generating pulses with multi-cycle duration. The motivation behind our research is to bridge the conventional ultrafast laser technology in the near-IR and the demand of ultrashort few-cycle energetic pulses in the mid-IR.