Projecte realitzat en col.laboració amb l'Institut de Ciències Fotòniques

Recently, there has been growing interest in ultrashort pulse measurement techniques. The aim of this work is to utilize interferometric autocorrelator in order to characterize near- IR femtosecond optical parametric oscillator (OPO) pulses. Although considerable research has been devoted to using nonlinear crystals in the autocorrelators, an attractive alternative to this approach remains two-photon absorption in photodiodes. In the setup we have used a commercial semiconductor which has several advantages to second harmonic generation technique. Conventional methods in autocorrelation analysis use secant hyperbolic square assumption to figure out the shape of pulse; but we have developed a software to find out the pulse shape by guessing the phase. The comparison between results from phase-guessing method and sech assumption shows that the first method is more flexible and gives much information but it needs to be enhanced in order to find the best phase automatically