Auto and cross correlation measurements of femtosecond laser beams in SRS microscope

Abstract

Ultrafast lasers are increasing their range of applications. In non-linear optical microscopy, the laser beam properties can influence the non-linear contrast efficiency and the image quality, so monitoring of the output waveform is often required.In order to obtain images, in Stimulated Raman Scattering (SRS) microscopy, two collinear laser beams, a high-power pump laser and a low power Stokes laser with different frequencies (ω L > ω S ) are focused into a sample. In this paper the two laser sources, in our case a femtosecond Ti:Sapphire (Ti:Sa) oscillator and a femtosecond synchronized optical parametric oscillator (OPO) are characterized by non-linear interferometric measurements. Taking advantage of two-photon absorption (TPA), autocorrelation measurements of each laser beam and cross correlation measurements of Ti:Sa and OPO are carried out. Results are reported and discussed.