Carrier-envelope phase measurement and stabilization of amplified Ti: sapphire femtosecond laser pulses by spectral interferometry

Carrier-envelope phase stabilization of amplified femtosecond laser pulses is demonstrated. An octave spanning white-light super-continuum is generated in a sapphire plate. Spectral interference was achieved between the blue component and the second harmonic of the red component of the super-continuum. Carrier-envelope phase information was extracted from the interference through Fourier transform and the phase was stabilized by refined modulation of pumping power of the oscillator through a phase locking loop. The root-mean-square value of the carrier-envelope phase locking error is lower than 80 mrad within the locking time of 3 h.