A type of glass modifications occurring after femto‐second laser irradiation gives rise to strong (10−2) from birefringence. This form birefringence is thought to be related to index nanostructure (called nanogratings). Analyzing induced tracks in fused silica using scanning electron microscopy (SEM) with nm resolution shows that nanostructures are porous nanoplanes with an average index lower than typical silica (Δn ∼ –0.20). Their origin is explained as arising from fast decomposition of the glass under localized, high‐intensity femtosecond laser radiation where strong nonlinear, multiphoton‐induced photoionization leads to plasma generation. Mechanistic details include Coulombic explosions characteristic of strong photoionization and the production of self‐trapped exciton (STE). Rapid relaxation of these STE prevents recombination and dissociated atomic oxygen instead recombines with each other to form molecular oxygen pointed out using Raman microscopy. Some of it is dissolved in the condensed glass whilst the rest is trapped within nanovoids. A chemical recombination can only occur at 1200 °C for many hours. This explains the thermal stability of such a nanostructure. Precise laser translation and control of these birefringent nanoporous structures allo arbitrarily tuning and positioning within the glass, an important tool for controlling optical properties for photonic applications, catalysts, molecular sieves, composites and more.

An insoluble chiral polymer-supported rhodium complex closely related to the soluble Rh(I)-diop complex (diop = 2,3-0-isopropylidene-2,3-dihydroxy-l,4-bis(diphenylphosphino)butane ( 1)) was prepared using a Merrifield resin. This insoluble system (suspended in benzene) catalyzes the asymmetric hydrogenation of aethylstyrene and methyl atrópate with a much lower efficiency than in solution, and ethanol inhibits the catalysis. In contrast, both catalytic systems, soluble and insoluble, are very efficient for asymmetric hydrosilylation of ketones (acetophenone, methyl benzyl ketone, isobutyrophenone). For a given ketone, the optical yield strongly depends upon the silane used. Dihydrosilanes (diphenylsilane, phenylmethylsilane, -naphthylphenylsilane) are always better than monohydrosilanes (triethylsilane, triethoxysilane, triphenylsilane). Optical yields up to 58 % were obtained. In all cases, the insoluble catalyst can be filtered and easily reused. ne of the most recent and important advances in asymmetric synthesis is the use of a soluble chiral catalyst. Soluble catalysts can be better defined than the heterogeneous ones, and in such complexes it is often easy to vary widely the steric and electronic environment of the catalytically active site in order to optimize both the chemical and optical yields of an asymmetric synthesis.The best results have been obtained in oligomerization of olefins with nickel catalysts2 3456or in reduction with a rhodium catalyst1•3-6 or cobalt complexes.7 8Optical yields as high as 70-90 % have been observed.However, in the use of a soluble catalyst, a problem of practical importance is encountered: the separation of the catalyst from the reaction products requires special treatment which usually destroy it. One way to solve this problem would be to fix the catalyst on a solid support in a way that retains the advantages observed in solution. Recently some authors described the introduction of phosphine groups into polystyrene. This phosphinated resin has been used as a ligand in rhodium or platinum complexes in order to catalyze the hydrogenation,8-10 hydrosilylation,9 10and hydroformyla-tion11 of olefins. In all cases, the insoluble catalyst (1) Part I: .

We ascertain by measuring the surface topography of a cleaved sample in which damage lines have been written in volume by scanning with a femtosecond laser, that matter shearing occur along the laser track with alternating sign (scissor or chiral effect). We note that the shearing in the head of the laser tracks change its sign with the change in scanning direction (pen effect or non reciprocal writing). We also show that nanostructures in the head are nano-shearing, with all the same sign whatever the direction of writing may be. We suggest that symmetries revealed by the shearing mimic the laser induced electron plasma density structures and inform on their unusual symmetries induced by the laser beam structures.