Research On Simulation Of Ultra-short Laser Pulse Spatio-temporal Characteristics

There are more and more applications of ultra-short laser pulse in science research and industrial production. In many applications the output beam quality of laser pulse optical systems needs to be contraled in order to meet these requirements. The surface errors and assembly errors in real optical systems have great influence on the laser pulse beam quality. So it has an important significance to simulate the pulse beam quality through optical systems and analyse the effects of system errors.The beam quality of laser pulse beam includes spatial characteristics and temporal characteristics. Spatial characteristics include focal spot size, pulse wave front, etc. while the temporal characteristics mainly mean the time width of output laser pulse. There are two ways to simulate the spatio-temporal characteristics. One numerical calculation method bases on Fresnel diffraction theory and Maxwell equations, the other bases on the combining of real ray tracing and diffraction integral. The former can not deal with the influence on pulse beam caused by optical system aberrations and errors. So we use the later method to simulate the pulse beam qulity in the paper. On this basis, this paper further analyses the effects caused by surface errors and assembly errors. Finaly, we design an experiment to verify our simulation.As a part of the National Natural Science Foundation of China called research of the effects on output high-energy short-pulse laser beam quality caused by actual errors of optical systems, this paper principal research content includes the surface error fitting by Zernike, ray tracing for surface with errors, spatial characteristics simulation, pulse width calculation and experimental verification, etc.