Control of Si-rich region inside a sodalime glass by parallel femtosecond laser focusing at multiple spots

Thermal modification and elemental distributions inside a sodalime glass were modified by parallel irradiation with focused 250 and 1 kHz femtosecond laser pulses at multiple spots. We found that the shape of a Si distribution was modified and the position of a Si-rich layer depended on the relative focal positions between 250 and 1 kHz laser pulses. We demonstrated the formation of a ribbon-shaped Si-rich glass of about 8 μm thickness and about 33 μm width by producing a line of a Si-rich layer by translating a glass sample perpendicular to the laser propagation axis. In addition, we simulated transient temperature distribution during laser exposure and discussed the role of 1 kHz laser irradiation in the modulation of elemental distributions

Condensation of Si-rich region inside soda-lime glass by parallel femtosecond laser irradiation

Local melting and modulation of elemental distributions can be induced inside a glass by focusing femtosecond (fs) laser pulses at high repetition rate (>100 kHz). Using only a single beam of fs laser pulses, the shape of the molten region is ellipsoidal, so the induced elemental distributions are often circular and elongate in the laser propagation direction. In this study, we show that the elongation of the fs laser-induced elemental distributions inside a soda-lime glass could be suppressed by parallel fsing of 250 kHz and 1 kHz fs laser pulses. The thickness of a Si-rich region became about twice thinner than that of a single 250 kHz laser irradiation. Interestingly, the position of the Si-rich region depended on the relative positions between 1 kHz and 250 kHz photoexcited regions. The observation of glass melt during laser exposure showed that the vortex flow of glass melt occurred and it induced the formation of a Si-rich region. Based on the simulation of the transient temperature and viscosity distributions during laser exposure, we temporally interpreted the origin of the vortex flow of glass melt and the mechanism of the formation of the Si-rich region

Media 1: Condensation of Si-rich region inside soda-lime glass by parallel femtosecond laser irradiation

Originally published in Optics Express on 30 June 2014 (oe-22-13-16493

Funding of an enterprise through the issue of bonds

<div><p>Autism spectrum disorder (ASD) has been postulated to involve impaired neuronal cooperation in large-scale neural networks, including cortico-cortical interhemispheric circuitry. In the context of ASD, alterations in both peripheral and central auditory processes have also attracted a great deal of interest because these changes appear to represent pathophysiological processes; therefore, many prior studies have focused on atypical auditory responses in ASD. The auditory evoked field (AEF), recorded by magnetoencephalography, and the synchronization of these processes between right and left hemispheres was recently suggested to reflect various cognitive abilities in children. However, to date, no previous study has focused on AEF synchronization in ASD subjects. To assess global coordination across spatially distributed brain regions, the analysis of Omega complexity from multichannel neurophysiological data was proposed. Using Omega complexity analysis, we investigated the global coordination of AEFs in 3–8-year-old typically developing (TD) children (n = 50) and children with ASD (n = 50) in 50-ms time-windows. Children with ASD displayed significantly higher Omega complexities compared with TD children in the time-window of 0–50 ms, suggesting lower whole brain synchronization in the early stage of the P1m component. When we analyzed the left and right hemispheres separately, no significant differences in any time-windows were observed. These results suggest lower right-left hemispheric synchronization in children with ASD compared with TD children. Our study provides new evidence of aberrant neural synchronization in young children with ASD by investigating auditory evoked neural responses to the human voice.</p></div

Sound waveform of the /ne/ voice stimulus.

<p>The total time of a /ne/ stimulus was approximately 342 ms; the time length of the consonant /n/ was approximately 65 ms; and the time length of the post consonantal vowel sound /e/ was approximately 277 ms. The time point of 50 ms after stimulation onset was defined as 0 ms, and the time-window of -50–0 ms was used as baseline period.</p

Omega complexity of AEFs for the left and right hemispheres in TD and ASD children.

<p>Omega complexities were calculated in 40 sensors corresponding to the left (A) and right (C) hemisphere. The Omega complexities of TD children and children with ASD were compared with unpaired two-tailed <i>t</i>-tests for 16 time windows in the left (B) and right (D) hemisphere. No significant differences were observed in any time-windows. AEF, auditory evoked field. TD, typically developing. ASD, autism spectrum disorder. The error bars represent 1 standard deviation.</p

Pearson correlation coefficients between Omega complexity in AEFs for the whole head and either age or K-ABC mental processing scale score for children with ASD (n = 50) and TD children (n = 50).

<p>Pearson correlation coefficients between Omega complexity in AEFs for the whole head and either age or K-ABC mental processing scale score for children with ASD (n = 50) and TD children (n = 50).</p