Inspired by previous theoretical work, experiments on diffraction of 10 femtosecond ultrashort pulses passing through a single slit have been performed. Fringes are dramatically reduced or even eliminated in the diffraction of 10 fs ultrashort pulsed laser in the near field compared with that of the continuous-wave laser. This can be explained in the frequency domain as a result of the broadband spectrum contained in ultrashort pulses. Simulations are performed for Fresnel diffraction for both 10 fs ultrashort pulsed and continuous-wave lasers and the results agree with the experimental observation. The results of this work have important implication in biomedical imaging and remote imaging applications to name only a few.