Anti-Stokes Cooling for Fluidics

流体的反斯托克斯冷却

• 批准号: 465090835
• 负责人: Professor Dr. Frank Cichos
• 金额: --
• 依托单位: Peter-Debye-Institut für Physik der weichen Materie
• 依托单位国家: 德国
• 项目类别: Research Grants
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/465090835?language=en
• 关键词: Anti; Stokes; Cooling; Fluidics

Temperature plays a ubiquitous role in physics, chemistry, biology, and engineering. Changing temperature may induce phase transitions, enhance or inhibit chemical reactions as well as speed up or slow down metabolic processes in organisms. Many fabrication methods rely on a well-defined temperature to proceed. Temperature differences drive thermodynamic machines. Yet, temperature is often only controlled as a global parameter of a system ensuring thermal equilibrium, e.g., by electric refrigerators or hot plates. Recently, metal nanoparticles have been shown to be effective light-controlled nano heat sources allowing to inject heat remotely at well-controlled positions in the sample. In this dynamically developing field of thermoplasmonics, local temperature increments have been employed, for example, in fluidic applications inducing thermophoretic solute drifts or thermo-osmotic liquid flows transporting and manipulating biological objects on small length scales. But light can be also used for refrigeration applications as demonstrated in the cooling and trapping of atoms or micromechanical systems to explore their quantum mechanical ground state. Most of those cooling experiments, however, proceed in vacuum, well isolated from a thermal bath. Within this project, we aim to bring laser refrigeration of nanocrystals to liquid environments for use in fluidic applications. Ytterbium-doped nanocrystals shall be optically cooled with the help of inelastic anti-Stokes scattering processes as recently demonstrated in D2O and vacuum. We will extend the applicability of such nanocrystals to an aqueous environment by studying different ways of surface passivation to exclude fast surface-related excited-state deactivation, which is supposed to be one of the processes preventing efficient cooling in water. Using Raman thermometry, we will measure the temperature of the nanocrystals and determine the efficiency of the cooling process. We will then use the nanocrystals as cold spots for fluidic applications, measuring thermo-osmotic interfacial flows created by the local temperature gradients. In combination with optically controlled heat sources, we will further explore the controlled generation of thermo-electric fields. Besides these fluidic applications, the ability to cool locally in condensed systems will open up a number of new possibilities also for the perturbation of biological species.

温度在物理，化学，生物学和工程中起无处不在的作用。温度变化可能会引起相变，增强或抑制化学反应，并加快生物体中的代谢过程。许多制造方法都依靠定义明确的温度进行。温度差异驱动热力学机器。但是，通常仅将温度作为系统的全局参数控制，以确保通过电冰箱或热板来确保热平衡。最近，金属纳米颗粒已被证明是有效的光控制的纳米热源，可以在样品中良好的控制位置远程注入热量。在这种动态发展的热浮游生物领域中，例如，在诱导嗜热溶质漂移或热渗透液流量运输和在小长度尺度上操纵生物学对象的局部温度增量。但是，光也可用于制冷应用，如原子或微机械系统的冷却和捕获中所证明的，以探索其量子机械基态。但是，大多数冷却实验在真空中进行，从热浴中很好地分离出来。在该项目中，我们旨在将纳米晶体的激光冷藏到用于流体应用中的液体环境中。如最近在D2O和真空中所证明的那样，应借助非弹性抗孔散射过程将掺杂的纳米晶体掺杂。我们将通过研究不同的表面钝化方式来排除与快速表面相关的激发状态停用效率，将这种纳米晶体的适用性扩展到水性环境中，这应该是防止水中有效冷却的过程之一。使用拉曼热法，我们将测量纳米晶体的温度，并确定冷却过程的效率。然后，我们将使用纳米晶体作为流体应用的冷点，测量局部温度梯度产生的热渗透界面流。结合光学控制的热源，我们将进一步探索热电场的受控产生。除了这些流体应用外，在冷凝系统中局部冷却的能力还将为生物种类扰动开辟许多新的可能性。