Modeling high density microholographic data storage: Using linear, quadratic, thresholding and hard clipping material characteristics

Crosstalk related raw signal-to-noise ratio (SNR) and bit error rate (BER) of high density bitwise microholographic data storage is investigated by numerical modeling. Scattering and diffraction of light is calculated in non-paraxial scalar approximation. A multiple thin slice implementation of the perturbative volume integral equation is used, which can be easily parallelized. The effect of bit and track spacing, and the different local characteristics of the holographic recording material on the SNR, BER and diffraction efficiency are investigated. The results show that these lateral spacing parameters have much more effect on crosstalk noise than the number of layers. Using two-photon, thresholding or hard clipping materials generates less crosstalk noise at the same data density than a linear material, and the dynamic range of these materials can be used more effectively resulting in higher single microhologram diffraction efficiencies.     

Steric hindrance in the synthesis and properties of the dimer of 1-(2,4,6-Tri-tert-butylphenyl)phosphole 1-oxide

Steric hindrance was observed during the oxidation of 2,4,6-tri-tert-butylphenylphosphole to the P oxide and in the dimerization of this latter species to the corresponding phosphanorbornene derivative. Single-crystal X-ray analysis of the dimer revealed considerable steric crowding around the P atoms. Deoxygenation of the dimer of the phosphole oxide by Cl₃SiH–C₆H₅N could only be accomplished under forcing conditions at 110°C. © 1997 John Wiley & Sons, Inc. Heteroatom Chem 8 : 527–531, 1997     

Synthesis of Silolide Dianions via Reduction of Dichlorosiloles: Important Role of the Solvent

The reduction of 1,1-dichloro-2,5-bistrimethylsilyl-3,4-diphenylsilole to silolide dianion by alkali metals was investigated. As previously demonstrated, the outcome of the reaction depends strongly on the applied alkali metal, solvent, reaction conditions, and substituent pattern. We showed that lithium is a powerful reducing agent in THF or DME solvents, the reaction is even faster than the same reaction with sodium. The X-ray structures of the corresponding dilithio and disodium silolide dianion were investigated, interestingly recrystallization of the dilithio salt results in a coordination polymer. In order to support the synthetic work DFT calculations were performed.     

Stereostructure of 8-chloro-5,6-di(methoxycarbonyl)-4,7-dimethyl-2-ethoxy-2-phosphabicyclo[2.2.2]octa-5,7-diene 2-oxide

The first X-ray structure of a phosphabicyclooctadiene, together with the NMR and mass spectral characterization of its isomers, is reported. © John Wiley & Sons, Inc.