Adiabatic Interactions and Frequency Conversion Processes: Investigations and Applications

强相干辐射与物质的相互作用是近年来激光科学研究的热点。这些相互作用不仅依赖于激光辐射的高强度，而且依赖于相干特性。在成功应用的相互作用的技术，绝热通过过程的基础上。这些是特别感兴趣的，由于其相对于实验参数的波动的鲁棒性。虽然绝热过程通常用中等强度的相当长的辐射脉冲来实现，但许多应用需要由高强度的短激光脉冲驱动的相互作用。我们将研究相干，绝热相互作用，短激光脉冲驱动，在量子系统中的应用，涉及多光子跃迁，在稠密的气体介质中快速退相过程，和非线性光学频率转换过程。调查集中在有效的低阶和高阶频率转换相干制备，气体介质的大密度。特别是，目的是提供新的，高效的短波长辐射源和超宽带光谱。这些是相当感兴趣的，例如，用于产生接近亚飞秒时域的超短激光脉冲。

Interactions of strong, coherent radiation with matter are of significant interest to recent laserbased science. These interactions do not rely on the high intensity of laser radiation only, but also on the coherence properties. Among the successfully applied interactions are techniques, based on adiabatic passage processes. These are of special interest due to their robustness with respect to fluctuations in the experimental parameters. While adiabatic processes are usually implemented with rather long radiation pulses at moderate intensities, many applications require interactions, driven by short laser pulses at high intensities. We will investigate coherent, adiabatic interactions, driven by short laser pulses, with regard to applications in quantum systems involving multi-photon transitions, in dense gaseous media with fast dephasing processes, and to nonlinear optical frequency conversion processes. The investigations focus on efficient low-order and high-order frequency conversion in coherently prepared, gaseous media of large densities. In particular, the aim is to provide novel, efficient sources for shortwavelength radiation and ultra-broadband spectra. These are of considerable interest, e.g. for the generation of ultra-short laser pulses, approaching the sub-femtosecond time domain.