Ultraviolet spectroscopy and thermodynamics of ultradense gas mixtures

在致密原子和分子介质的吸收和发射线之间，例如高压下的染料溶液和碱性缓冲气体混合物，在许多情况下存在普遍的热力学标度，Kennard-Stepanov关系，详细平衡的表现。在初步工作中，这使我们的小组能够证明光子的第一个玻色-爱因斯坦凝聚，以及碰撞诱导的气体激光冷却的第一个演示。该研究项目的近期目标是演示一种新的光谱方法来确定绝对温度。在计划进行的调查的框架内，吸收和发射光谱测量进行了初步工作的密集合奏，碰撞加宽达到热能的频率单位，将扩大到样品已经在室温下的气体。我们打算研究惰性气体氙以及小分子的气体混合物，例如，在100-200巴压力下，氩气作为缓冲气体，这将通过在紫外和真空紫外光谱区域的测量成为可能。通过记录高气体密度下的吸收和发射光谱，可以验证原子和分子气体混合物的热力学Kennard-Stepanov关系，这应该允许温度的光学频率测量。这项工作的未来前景是在真空紫外光谱范围内实现玻色-爱因斯坦凝聚，作为该波长范围内的相干光源，这对于通常的激光器来说很难获得，例如光刻或医疗应用。这项工作也将形成实验的基础上碰撞诱导激光冷却的“宏观”合奏致密气体从室温开始。

Between the absorption and emission lines of dense atomic and molecular media, such as dye solutions and alkali buffer gas mixtures at high pressure, in many cases there exists a universal thermodynamic scaling, the Kennard-Stepanov relation, a manifestation of detailed balance. In preliminary work, this enabled our group to demonstrate the first Bose-Einstein condensation of photons, as well as the first demonstration of collisionally-induced laser cooling of gases. The immediate goal of this research project is the demonstration of a new spectroscopic method for the determination of the absolute temperature. In the framework of the planned investigations, spectroscopic measurements of absorption and emission performed in preliminary work on dense ensembles, where the collisional broadening reaches the thermal energy in frequency units, will be extended to samples which are already gaseous at room temperature. We intend to investigate gas mixtures of the noble gas xenon, as well as small molecules, with, for example, argon as a buffer gas at 100-200 bar pressure, which will be made possible by measurements in the ultraviolet and vacuum ultraviolet spectral regions. By recording absorption and emission spectra at high gas densities, the thermodynamic Kennard-Stepanov relation for atomic and molecular gas mixtures can be verified, which should allow an optical frequency measurement of the temperature. A future perspective of the work is the realization of Bose-Einstein condensates in the vacuum-ultraviolet spectral regime, as coherent sources of light in this wavelength range, which is difficult to access for usual lasers, for example for lithography or medical applications. The work will also form the basis for experiments on collisionally-induced laser cooling of "macroscopic" ensembles of dense gases starting from room temperature.