关键词: 飞秒脉冲, 小孔衍射, 近场衍射 , 格林函数

Abstract: By using the method for the numerical calculation of Green's function, the light field of the femtosecond laser pulses through a subwavelength aperture is simulated and calculated. The timedependent laser pulse with Gauss profile is decomposed into a series of monochromatic simple harmonic waves firstly. For the light field of the harmonic wave with a single frequency, the numerical calculation is made and the light fields in the space domain are received. Such numerical solution is iterated for all the waves with different frequencies, and all the numerical solutions are transformed into the light fields in the time domain by inverse Fourier transform. Through analysis, it is found that the femtosecond laser pulses propagate the both sides of the aperture along the medium interface, and during the propagating process, the diffraction light fields form the intensity nodes on the medium interface and in the near domain.

Key words: nearfield diffraction , Green's function, pinhole diffraction, femtosecond laser pulse