Control of carrier-envelope phase offset in femtosecond laser with PLL and TV-Rb clock

With the fast development of the cycle-pulse lasers, the control of the carrier-envelope phase offset (CEO) frequency has been an important research subject in such fields as femtosecond optical frequency metrology, strong field physics and high harmonic generation. In this paper, a different measurement method for CEO is demonstrated and subsequently a better beat frequency signal with the signal-to-noise ratio greater than 40 dB is obtained. Based on this optimized beat frequency signal, the CEO of the Ti: sapphire laser is stabilized to the standard signal of 10 MHz of the microwave reference source TV-Rb clock by using the electronic phase-locked loop techniques and the piezo-transducers which are mounted on the mirror inside the laser cavity to change the frequency and phase. The repetition rate of the Ti: sapphire laser is locked to the same TV-Rb clock simultaneously. The experimental results showed that the stability of the repetition rate reached the same level as the TV-Rb clock and that of the CEO frequency was increased by three orders.