Investigations of the Talbot effects for a grating illuminated by the ultrashort optical pulses

Based on the theories of the Fresnel diffraction and the signal processing, the Talbot effects for a grating illuminated by a train of ultrashort optical pulses are investigated numerically. Influences of the input pulse parameters and the grating structure on the Talbot images are discussed detailedly. Results demonstrate that the contrast of the high/low field boundary becomes obscure for the optical pulse with shorter temporal duration and chirp. And a grating with smaller duty cycle (DC) is easier to the formation of constructive interference field. In addition, although the high/low field distribution resembles as the image of grating period at the integer Talbot detecting planes, it repeats k-times at the fractional Talbot detecting plane, which can be exploited for obtaining higher pulse repetition rate multiplication.