Abstract：We present intensity distributions of a supercontinuum laser passing through an apertured dispersion lens and find focal shift effects generated. The results show that, apart from the conventional negative focal shift, a positive focal shift also appears in the supercontinuum laser. The maximum intensity of the supercontinuum laser shifts toward the lens when the truncated parameter is small. However, it exceeds the focus of the central wavelength and a positive focal shift appears in the supercontinuum laser with large truncated parameter. Both of the maximum intensities shift away from the focus when the bandwidth of the supercontinuum laser increases, while the shift direction is opposite. No focal shift appears when the bandwidth and the truncated parameter satisfy some conditions.
2015, Vol. 32 
