Biomedical subjects

Tetsu Ito

Publications and source records attributed to Tetsu Ito.

2 recordsLinked to original sources

PubMed2004

Speckle correlation measurement in a disordered medium observed through second-harmonics generation.

We examined speckle correlation in a disordered medium consisting of LiNbO3 corpuscles, by observing the total intensity of the second-harmonics (SH) light generated by angular correlated two excitation beams. The total SH intensity showed a correlation peak at theta approximately 0, where theta was the angle between two excitation beams, and decreased as theta was increased. The observation could be understood as the effect of the constructive interference between two volume speckle patterns produced by the excitation beams inside the medium, and the peak could reflect the mutual correlation between two patterns. The experimental results showed good agreements with a theoretical analysis based on a diffusion approximation.

Journal Article↗

PubMed2002

Polarization-dependent laser action in a two-dimensional random medium.

We examined laser action in a two-dimensional amplifying and scattering medium consisting of random array of dye-doped plastic fiber. When the excitation pulse energy was increased, the parallel emission component to the fiber first reached the laser threshold showing spectral collapse, and then further increase in the excitation pulse energy resulted in the subsequent laser action in the perpendicular component. Two-beam spatial-correlation measurement was performed to examine the gain regions. It was found that the size of the gain region is different between the two polarization components. Experimental results on the threshold and the gain region are discussed on the basis of simple rate equations.

Journal Article↗