Estimation chirp in ultrashort laser pulses using interferometric autocorrelation envelope width

A simple method was presented to determine various higher order chirps in ultrashort laser pulses based on interferometric autocorrelation (IAC) envelope width.This method is highly sensitive to chirp,dependence of envelope width of IAC on different magnitude of the chirp and its order.Through the Gaussian intensity of the linear chirp,square and cubic chirp pulses were analyzed and numerical calculated,IAC envelope width as a functions of the normalized mean chirp for different orders of chirp were obtained.The theoretical analysis was supported by experimental envelope width,IAC signals obtained using laser chirped pulses from a CW dye ring laser in the colliding pulse mode (CPM) locked regime.According to the characteristics of IAC envelope,the square chirp pulse was determined,the envelope width was measured 1.15 and the chirped ultrashort laser pulse was measured 1.0.The results show that the order of chirp can be determined according to the chirp characteristics of the two wings of IAC envelope and that the value of the chirp can be estimated according to its dependence on the envelope width. Chirp of ultrashort laser pulses can be determined easily based on the IAC envelope width.