In this paper, diffraction of the supercontinuum beam from aperture and lens are described for the first time. We study the positive and negative focal shift effects of the supercontinuum laser on focusing system in detail. It is found that, apart from the conventional negative focal shift, the positive focal shift is also generated in the supercontinuum laser. The maximum intensity of the focused supercontinuum laser is shifted toward the lens with small truncated parameter. When the truncated parameter is large, however, the maximum intensity...
