Femtosecond kHz laser/amplifier system with optical parametric amplifier (OPA), pumped through the main unit and usable only through this.

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The research of the working group "Ultrafast spectroscopy and biophysics" lies in the field of fast and ultrafast molecular dynamics in condensed phase. We are particularly interested in reactive and non-reactive photoinduced processes in biologically relevant molecules and corresponding model systems, as well as in metal-ligand complexes. The understanding of the competing deactivation processes of a matrix-bound chromophore on the pico- and sub-picosecond time scale after electronic excitation on the molecular level is the basis for the use of the reaction and process mechanisms based on this for applications e.g. in biological-medical (fluorescence markers, optogenetics) and in technical fields (catalysis, luminescence, magnetism).Ultrafast methods of "pump/probe" laser spectroscopy are applied and further developed in order to investigate the light-induced primary processes with high time-resolution into the femtosecond time-range. These include time-resolved absorption spectroscopy in the visible and adjacent spectral ranges for recording electronic dynamics, time-resolved absorption spectroscopy in the mid-infrared for recording ultrafast vibrational and structural dynamics and time-resolved reflectivity spectroscopy in the visible spectral range for describing electronic dynamics in solid samples. As a complementary method, the mentioned infrared spectroscopy is indispensable. Therefore, the object of this application is the procurement of a femtosecond kilohertz laser/amplifier system with an optical parametric amplifier as a replacement for an old device. The total time required to obtain usable measurement results has now increased by a factor of about 2-5 and is absolutely no longer justifiable. The device no longer corresponds in any way to the current standard of apparatus technology with which internationally competitive scientific results could be achieved. One of the consequences of this is that our infrared-spectroscopic measurements within the framework of the DFG Collaborative Research Centre, DFG Research Grant and Research Centre of the State of Rhineland-Palatinate can currently no longer be carried out with the desired and required intensity. The ongoing and planned scientific projects of the working group require excitation pulses that can be tuned to a wide spectral range (ultraviolet - near infrared), with sufficiently large pulse energy, especially in the ultraviolet range. Therefore, an optical parametric amplifier is proposed for the femtosecond kilohertz laser/amplifier system, which is pumped through the amplifier system and can only be used through it.