Detection efficiency and bandwidth optimized electro-optic sampling of mid-infrared waves

This thesis investigates the detection efficiency of field-resolved measurements of ultrashort mid-infrared waves via electro-optic sampling for the first time.

Employing high-power gate pulses and phase-matched upconversion in thick nonlinear crystals, unprecedented efficiencies are achieved for octave-spanning fields in this wavelength range.

In combination with state-of-the art, high-power, ultrashort mid-infrared sources, this allows to demonstrate a new regime of linear detection dynamic range for field strengths from mV/cm to MV/cm-levels.

These results crucially contribute to the development of field-resolved spectrometers for early disease detection, as fundamental vibrational modes of (bio-)molecules lie in the investigated spectral range. The results are discussed and compared with previous sensitivity records for electric-field measurements and reference is made to related implementations of the described characterization technique.

Including a detailed theoreticaldescription and simulation results, the work elucidates crucial scaling laws, characteristics and limitations.

The thesis will thus serve as an educational introduction to the topic of field-resolved measurements using electro-optic sampling, giving detailed instructions on simulations and experimental implementations.

At the same time, it showcases the state-of-the-art in terms of detection sensitivity for characterizing mid-infrared waves.