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

我的研究目标是控制复杂量子材料在超短光脉冲作用下的宏观特性。通过这一建议，我们将建立一种新的光谱，以解决在定制的低温电磁环境中样品的中红外振动和电子模式共振激发的实验关键问题。我们将实现一个多维泵浦和探针装置，能够测量复杂量子材料的光学导电性的时间演变，随后是振动，电子或磁性的低能量模式的多重谐振驱动。在这里，我提出了一种新的光谱方法，能够测量介电函数在3eV （400nm）到0.1 ev （0,015mm）的宽能量范围内的微小变化，随后在中红外范围内多次激发。为了在中红外和可见光中产生足够的激光脉冲，我们将购买能够以高重复率（50KHz）提供超短高能脉冲（每脉冲能量>1.5mJ）的激光系统。光源产生的激光脉冲应分为四个脉冲，一个用于产生太赫兹脉冲（1028 nm），以及3个泵浦光参量放大器（OPA），用于产生在可见光和中红外范围内可调谐的本质同步脉冲。详细的OPA有：1)双OPA和差频产生，产生在5-20m之间可调谐的CEP中红外脉冲（Epp>1µJ从5到15µm）；2)中红外OPA范围为=2µm ~ 10µm， Epp范围为1µJ；3)可见光OPA在600 ~ 900nm之间可调（脉冲持续时间<30fs）。激光系统将提供独立可调谐的中红外脉冲，能够共振驱动低能量激发，如声子模式、电子间隙（超导和CDW）和自旋激发。这样的光源将成为通过多重光激发控制超导实验的支柱。该研究单元将允许测量大波长范围（从400到10000nm）单次40KHz的光激发响应。在高重复率的可见光脉冲的整形将使随机基于光谱与中红外激发方案。

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.