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制冷机，具有沿沿着三个轴的光学通道，包括一个分裂对电磁体以及x-y-z和旋转纳米定位，用于组合的电学和光学测量。因此，需要具有大NA的低温物镜。为了综合测量新型货车德瓦耳斯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，需要利用电场、磁场、毫开尔文温度以及附加的光学和电子设备进行原位操作。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，波长范围从550 nm到1000 nm的超窄连续可调谐激光系统是必不可少的。量子纳米系统的光学响应将用三级拉曼光谱仪进行分析，该光谱仪配备了用于杂散光抑制的减法模式和用于增强能量分辨率的加法模式。被分析的光被记录， 灵敏的CCD相机或用于ICCD的时间分辨测量（> 200 ps）。这种独特的设置将用于研究多重相互作用现象，例如电子-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（量子）相变在新的量子纳米系统。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.