Effect of spectrum property on a focused supercontinuum laser

Fields of a focused supercontinuum laser with different center wavelength are studied near the focus in this paper. Effects of the spectrum property on the intensity distributions of the laser are analyzed in detail by numerical calculations. The results indicate that the maximum intensity is shifted toward the lens as the center wavelength decreases and it is deviated from the lens as the center wavelength shift to long wavelength. Influence of the center wavelength on the shift of the maximum intensity is smaller in the laser with broader bandwidth. Determined by the center wavelength, the focused supercontinuum laser presents positive focal shift or negative focal shift in the system with any truncated parameter. If appropriate center wavelength and bandwidth are chosen, the focal shift of the supercontinuum laser passing through a dispersive lens can be eliminated.