Opacity effect on extreme ultraviolet radiation from laser-produced tin plasmas

Opacity effects on extreme ultraviolet (EUV) emission from laser-produced tin (Sn) plasma have been experimentally investigated. An absorption spectrum of a uniform Sn plasma generated by thermal x rays has been measured in the EUV range (9-19 nm wavelength) for the first time. Experimental results indicate that control of the optical depth of the laser-produced Sn plasma is essential for obtaining high conversion to 13.5 nm-wavelength EUV radiation; 1.8% of the conversion efficiency was attained with the use of 2.2 ns laser pulses.</p

Angular distribution control of extreme ultraviolet radiation from laser-produced plasma by manipulating the nanostructure of low-density SnO 2 targets

金沢大学先端科学・社会共創推進機構We have found that the divergence of a relatively monochromatic extreme ultraviolet (EUV) emission from a laser-produced plasma can be manipulated by changing the target morphology which is a porous low-density tin oxide (Sn O2) structure. The fundamental light of a Nd-YAG laser was irradiated on the target with laser intensity of ∼ 1011 W cm2 and pulse duration of 10 ns. The nanostructure and density of the targets were tuned by a combination of colloidal polymer template and sol-gel processes [Gu, Nagai, Norimatsu, Fujioka, Nishimura, Nishihara, Miyanaga, and Izawa, Chem. Mater. 17, 1115 (2005)], which has a merit in large-scale preparation. When the target has an open cell nanostructure, the EUV emission directed predominantly along target normal, while a closed cell target exhibited divergent emission. The angular distribution may be affected by the orientation of the microstructured initial target, and this phenomenon can be applied to wavefront control of EUV emission. © 2006 American Institute of Physics.Embargo Period 12 month

Synthesis and properties of σ-π conjugated porous polymers obtained with Mizoroki–Heck reaction of tetra vinyl cyclic siloxane with dibromo fluorene

sigma-pi Conjugated porous polymers were synthesized by the Mizoroki-Heck reaction of cyclic siloxane with vinyl groups, 1,3,5,7-tetravinyltetramethylcyclotetrasiloxane (TVMCTS), and 2,7-dibromo-9,9-dialkylfluorene (RFl) compounds, using a Pd catalyst inN,N-dimethylformamide (DMF) at 100 degrees C. The reactions of TVMCTS in combination with 2,7-dibromo-9,9-dihexylfluorene (HFl), 2,7-dibromo-9,9-dioctylfluorene (OFl), and 2,7-dibromo-9,9-ethylhexylfluorene (EHFl) yielded porous polymers whose morphologies were induced by phase separation during the network formation. The reactions in combination with binary RFl systems, TVMCTS-HFl/OFl, and HFl/EHFl systems, also yielded porous polymers. Scanning electron microscope images showed porous structures, which were composed by connected globules and/or isolated-deformed holes. The long and branching structure of the alkyl side chains in RFl decreased Young's modulus of porous polymers in compression test. The porous polymers showed emission derived from sigma-pi conjugated fluorene units on photo excitation. An increase in monomer concentration in the reaction induced red shifts of the emission bands of the porous polymer due to pi-stacking of the fluorene units. The porous polymers showed relatively high fluorescence quantum yields of about 0.2-0.3. Quantum yield of the porous polymers with HFl decreased with increasing monomer concentration in the reaction systems