Near infrared spectroscopy assessment of the glucose solution processed by ultrasonic cavitation.

The near infrared (NIR) absorption was investigated on the glucose aqueous solutions with various optical pathlengths (PLs) and processed by ultrasonic cavitation. In water, the strong absorption peak at a wavelength of 1430 nm, appeared in the case of short PL, was separated into several peaks in the case of wide PL due to increasing the number of H(2)O clusters. In a d(+) glucose solution, it was seen that NIR absorption was reduced at peculiar wavelengths of 970 nm and 1130 nm and its profile changed in a capricious manner in the region from 1300 nm to 1600 nm. The cavitation generated lots of OH(-) ion in water and made the capricious absorption profile regularly graded with the cavitation time toward less-absorptive direction. These effects are supposed to be caused by the dipole moments of H(2)O clusters arranged by the interaction between them and generated basic OH ions. The statistical principal component regression (PCR) and partial least-squares (PLS) regression demonstrated that the treatment of UC was helpful to enhance the glucose sensitivity.

Restoration of the intensity profile of a focused laser spot by means of combining optical correlation with a numerical method.

A method is presented by which intensity profile of a focused light spot is reconstructed from the correlation pattern between itself and a pinhole, which is obtained by moving the focused spot with the aid of an acousto-optic deflector (AOD). The pattern was formulated into a matrix equation by assuming that it was circular symmetric and was approximated by a number of linear functions. The results were numerically given by solving the matrix equation with a modified least-squares method and were assessed for the degree of focus, influence of signal fluctuations, and degradation of the spot resulting from heat generation within the AOD.

Calculation of the bistability in detuned nonlinear prism coupling.

With the help of the Laplace and its inverse transformations, the bistable characteristics in detuned coupling to a diffusive nonlinear guide were numerically evaluated.