Closed-cycle optical millikelvin magnet cryostat system for high-precision spectroscopy of lowest energy excitations

应用系统的主要部分是一个光学稀释式制冷机，它具有沿三个轴的通道，包括一个分裂对电磁铁以及用于光电联合测量的x-y-z和旋转纳米定位。因此，需要一种具有大NA的低温物镜。对于新型范德华异质结构和调制量子纳米结构中的光学带间跃迁、低能集体激发以及量子态的输运性质的联合测量，需要毫秒级的温度以及附加的光学和电子设备。更详细地说，对于共振非弹性光散射实验和光致发光激发光谱，在550 nm到1000 nm的波长范围内的超窄连续可调激光系统是必不可少的。利用三级拉曼光谱仪分析量子纳米系统的光学响应，其中减法模式用于杂散光抑制，加法模式用于提高能量分辨率。所分析的光可以用灵敏的CCD相机记录，也可以用ICCD进行时间分辨率测量(&gt；200ps)。这种独特的装置将被用来研究多重相互作用现象，如电子-电子、电子-声子、自旋谷等相互作用，以及由这些相互作用驱动的新兴现象，如超导或新型量子纳米系统中的(量子-)相变。我们的目标是对这些迷人的系统有一个基本的了解，并在下一步学习有目的地修改和调整它们的属性。

The major part of the applied system is an optical dilution refrigerator with optical of access along three axes using including an split-pair electromagnet as well as x-y-z and rotational nano-positioning for combined electrical and optical measurements. Therefore, an low-temperature objective with large NA is required. For the combined measurements of optical interband transition, low-energy collective excitations as well as transport properties of quantum states in novel van der Waals heterostructures and modulated quantum nano-structures that can be in-situ manipulated with electric and magnetic fields, millikelvin temperatures as well as additional optical and electronic equipment are required. In more detail, for resonant inelastic light scattering experiments and for photo-luminescence excitation spectroscopy, an ultra-narrow continuously tunable laser system in the wavelength range from 550nm to 1000nm is essential. The optical response of the quantum-nano-systems will be analyzed with a triple stage Raman spectrometer equipped with subtractive mode for stray light rejection and additive mode for enhancement of the energy resolution. The analyzed light is recorded either with a sensitive CCD camera or for time resolved measurements (>200ps) with an ICCD. This unique set-up will be used to study multiplex interaction phenomena as e.g. electron-electron, electron-phonon, spin-valley etc. interactions as well as emergent phenomena that are driven by these interactions such as superconductivity or (quantum-)phase transitions in novel quantum nano-systems. The goal is to develop a fundamental understanding of these fascinating systems and to learn in a next step to modify and tune their properties on purpose.