| For ultra-short laser pulses have the advantages of high peak power and very narrow temporal,they are applied in many fields.Consequently,it is vital to develop the method of measuring ultrashort pulses which is different to traditional method.Due to spatial-temporal distortions produced in the propagation of ultrashort pulses,it is increasingly difficult to measure these pulses existed spatial-temporal distortions.In this essay,pulses with spatial-temporal distortions were investigated based on Frequency-Resolved Optical Gating(FROG),in order to discover the change of spatial-temporal distortions on phase and pulse width of pulses.Meanwhile,by controlling the distortions,the effects on measurement were studied as well.The essay mainly includes the following aspects:Firstly,the invention and development of measurement of ultrashort pulses were reviewed.The characterizations of different measurement methods were discussed,especially,Second-Harmonic-Generation Frequency-Resolved Optical Gating(SHG-FROG)and Grating-Eliminated No-nonsense Observation of Ultrafast Incident Laser Light E-fields(GRENOUILLE)which was simplified from FROG.Their fundamental principles and demodulated technologies were analyzed and discussed in detail.In addition,the GRENOUILLE system was constructed,and the location of nonlinear crystal was analyzed.Moreover,temporal and spatial calibrations through experiment on the GRENOUILLE system were investigated.Finally,the pulses passing through apertures with different diameters and glass chips with different thickness were measured by GRENOUILLE system and were reconstructed.After FROG traces were pretreated and consistently check,accuracy information of pulses were obtained.The results showed that the diameter of apertures have an apparent effects on phase of pulses and its effects on pulses width can be neglect.And the thickness of glass has a remarkable effect on pulse width which results from dispersion and has little effect on phase. |
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