High repetition rate high power laser system for mid-IR experiments

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My research goal is to control of the macroscopic properties of complex quantum materials in interaction with ultrashort light pulses. Through this proposal we will establish a novel spectroscopy to address experimentally key aspects on the resonant excitation of mid-IR vibrational and electronic modes for samples in a tailored cryogenic electromagnetic environment. We will implement a multidimensional pump and probe setup capable to measure the time evolution of the optical conductivity of complex quantum materials subsequently to the multiple resonant drive of low energy modes of vibrational, electronic or magnetic nature. In detail here I propose a novel spectroscopic approach capable of measuring small changes in the dielectric function on a broad energy range from 3eV (400nm) to 0,1eV(0,015mm) subsequently to multiple excitation in the mid-IR range. In order to produce adequate laser pulses in the mid-IR and visible we will purchase a laser system capable of delivering ultrashort high energy pulses (energy per pulse>1.5mJ) at high repetition rate (50KHz). The laser pulse produced by the source should be divided into four pulses, one used to generate THz pulses (at 1028 nm), and 3pumping optical parametric amplifiers (OPA) designed to produce intrinsically synchronized pulses tuneable in the visible and mid-IR range. In detail the OPA are: 1) Twin OPA and difference frequency generation to generate CEP mid-IR pulses tuneable between 5-20m (Epp>1µJ from 5 to 15µm); 2) Mid-IR OPA from =2µm to 10µm with Epp>1µJ on all the range; 3) Visible OPA tuneable between 600 and 900nm (pulse duration<30fs). The laser system will deliver independently tuneable mid-IR pulses capable of resonantly drive low energy excitations such as phonon modes, electronic gaps (superconducting and CDW) and spin excitation. Such a source will be the back bone of experiments aimed at controlling the superconducting through multiple photo-excitations. The research unit will allow for the measurements of the response to photo-excitation on a large wavelength range (from 400 to 10000nm) single shot at 40KHz. The shaping of visible light pulses at high repetition rate will enable stochastic based spectroscopy with mid-IR excitations schemes.