The photodetachment of a triatomic negative ion is studied and the detached-electron wave function is obtained as a superposition of coherent waves originating from each atom of the system. The photodetached electron flux is evaluated on a screen placed at a large distance from the system, which displays strong interferences. A simple analytical formula is also obtained for the total photodetachment cross section. The formula approaches one time the cross sections for the one-center and two-center systems in the high photon energy limits. Also it approaches three times the cross section for one-center system in the low photon energy limits.

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In this paper we perform a simulation of fiber Bragg grating sensor with different grating lengths. It is shown that the grating length represents as one of the critical parameters in contributing to a high performance fiber Bragg grating sensor. The simulated fiber gratings with different lengths were analyzed and designed by calculating reflection and transmission spectra, and the bandwidth. Such simulations are based on solving coupled mode equations that describe the interaction of guided modes. The coupled mode equations are solved by the Transfer Matrix Method (a fundamental matrix method).

This study deals with Nd:YAG laser cutting nonmetallic materials, which is one of the most important and popular industrial applications of laser. The main theme is to evaluate the effects of Nd:YAG laser beam power besides work piece scanning speed. For approximate cutting depth, a theoretical study is conducted in terms of material property and cutting speed. Results show a nonlinear relation between the cutting depth and input energy. There is no significant effect of speed on cutting depth with the speed being larger than 30 mm/s. An extra energy is utilized in the deep cutting. It is inferred that as the laser power increases, cutting depth increases. The experimental outcomes are in good agreement with theoretical results. This analysis will provide a guideline for laser-based industry to select a suitable laser for cutting, scribing, trimming, engraving, and marking nonmetallic materials.

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