当前位置: X-MOL 学术Chirality › 论文详情
Our official English website, www.x-mol.net, welcomes your feedback! (Note: you will need to create a separate account there.)
Understanding laser desorption with circularly polarized light
Chirality ( IF 2 ) Pub Date : 2020-10-08 , DOI: 10.1002/chir.23279
Florian Ristow 1 , Jakob Scheffel 1 , Xuqiang Xu 2 , Natalie Fehn 2 , Katrin E. Oberhofer 1 , Johann Riemensberger 1 , Farinaz Mortaheb 2 , Reinhard Kienberger 1 , Ulrich Heiz 2 , Aras Kartouzian 2 , Hristo Iglev 1
Affiliation  

We present aspects of emerging optical activity in thin racemic 1,1′‐Bi‐2‐naphthol films upon irradiation with circularly polarized light and subsequent resonant two‐photon absorption in the sample. Thorough analysis of the sample morphology is conducted by means of (polarization‐resolved) optical microscopy and scanning electron microscopy (SEM). The influence of crystallization on the nonlinear probing technique (second harmonic generation circular dichroism [SHG‐CD]) is investigated. Optical activity and crystallization are brought together by a systematic investigation in different crystallization regimes. We find crystallization to be responsible for two counter‐acting effects, which arise for different states of crystallization. Measuring crystallized samples offers the best signal‐to‐noise ratio, but it limits generation of optical activity due to self‐assembly effects. For suppression of crystallization on the other hand, there is a clear indication that enantiomeric selective desorption is responsible for the generation of optical activity in the sample. We reach the current resolution limit of probing with SHG‐CD, as we suppress the crystallization in the racemic sample during desorption. In addition, intensity‐dependent measurements on the induced optical activity reveal an onset threshold (≈0.7 TW cm−2), above which higher order nonlinear processes impair the generation of optical activity by desorption with CPL.

中文翻译:

了解圆偏振光的激光解吸

我们介绍了圆偏振光辐照后样品中消旋的1,1'-Bi-2-萘酚薄膜中正在出现的光学活性方面,以及随后的共振双光子吸收现象。通过(偏振分辨)光学显微镜和扫描电子显微镜(SEM)进行样品形态的全面分析。研究了结晶对非线性探测技术(二次谐波产生圆二色性[SHG-CD])的影响。光学活性和结晶作用通过对不同结晶形式的系统研究而结合在一起。我们发现结晶是造成两种反作用的原因,这是由于结晶状态不同而引起的。测量结晶样品可提供最佳的信噪比,但是由于自组装效应,它限制了光学活动的产生。另一方面,为了抑制结晶,有明确的迹象表明对映异构体选择性解吸负责样品中光学活性的产生。由于我们在解吸期间抑制了外消旋样品中的结晶,因此达到了用SHG-CD进行探测的当前分辨率极限。此外,对诱导的光活动的强度依赖性测量揭示了起始阈值(≈0.7TW cm 因为我们抑制了解吸过程中外消旋样品中的结晶。此外,对诱导的光活动的强度依赖性测量揭示了起始阈值(≈0.7TW cm 因为我们抑制了解吸过程中外消旋样品中的结晶。此外,对诱导的光活动的强度依赖性测量揭示了起始阈值(≈0.7TW cm-2),在此之上,高阶非线性过程会损害CPL解吸产生的光学活性。
更新日期:2020-11-21
down
wechat
bug