Papers by Author: Young Chul Kim

Abstract: The characteristics of the e-beam have been investigated according to the various parameters of the wiggler in a miniaturized free electron laser (FEL) module by using 3-dimensional (3D) simulations. The e-beam emerging from the electron emitter was made parallel by applying a static bias to the middle electrode of the electron lens set. It was found that the width of the wiggler electrodes had great effect on the e-beam trajectory inside the wiggler.

Abstract: We have annealed the thin layer of the amorphous silicon (a-Si) using the Q-swtiched Nd:YAG laser pulses in order to transform the a-Si into polycrystalline silicon (poly-Si) and investigated the crystalline structures of the poly-Si. Before illuminating the light to the layer, the frequency of the laser was doubled through the second harmonic generation (SHG) process to enhance the absorption efficiency of the optical energy. When the optical energy was higher than 500 mJ/cm², we could obtain the micro-crystalline structure with grain size as large as 500 nm.