| Abstract: | Theory of Optimum Focusing for Direct Higher Optical Harmonics Generation Optimum focusing conditions for Gaussian beams for direct higher harmonics generation are derived neglecting the pump-wave depletion. The conditions for optimum focusing are obtained numerically and in the limits of weak and strong focusing analytically. The results show that at optimum conditions strong focusing is favourable. The power of the m-th harmonics for m > 3 is proportional to  focusing parameter, L medium length, b confocal parameter of the pump wave). Numerical results are given for odd and even (up to the seventh) harmonics. |
