Group theory and experiments on helical and linear distributed feedback gas lasers

Novel Aspects Of Far-Infrared Gas Lasers

“…The concept of helical feedback (HFB) which is based on group theory [13, 19j was first verified on an optically pumped farinfrared gas laser equiped with a helical waveguide for optical feedback [13,18,19]. In the meanwhile it was noticed that HFB is also present in, dye lasers with cholesteric liquid crystals serving as optical feedback [10,11,16,20].…”

“…The successful coupled-wave theory [9][10][11] is relevant for the far-infrared DFB gas lasers. Therefore, these have been applied to test this theory [4,5,[12][13][14][15][16]. On the other hand, they are not suited for a study of DFB with strong axially periodic modulations [16][17].…”

Synthesis and Supramolecular Organization of 5-(4-Alkylphenyl)isatin

“…Supramolecular organization of chromophores is essential for many high-tech applications, such as laser technology, nonlinear optics, , or supramolecular photochemistry…”

“…Supramolecular organization of chromophores is essential for many high-tech applications, such as laser technology, 1 nonlinear optics, 2,3 or supramolecular photochemistry. 4 Common approaches to achieve a desired supramolecular alignment are the following: embedding of chromophoric guests in polymeric, crystalline, or liquid-crystalline host matrices, as well as covalent insertion of chromophoric monomers into the main-chain or into side-chains of polymers.…”

“…However, considering the selectivity problems and the chromatographic separation of the 4-alkylphenyl boronic acids, our new method provides no significant advantage compared to the traditional sequence. The boronic acid intermediates 2aÀe were coupled with 5-bromoisatin (1) under SuzukiÀMiyaura conditions to the desired 5-(4-alkylphenyl)isatins 3aÀe. As can be seen from Table 1, the yields of this SuzukiÀMiyaura coupling were only moderate but delivered enough material for the further studies.…”