Abstract

Sum-frequency-mixing (SFM) and second-harmonic-generation (SHG) within a femtosecond optical parametric oscillator (OPO) provide a practical means of creating the short parent pulses needed to coherently synthesize sub-femtosecond pulses over a wide visible bandwidth. A major obstacle is that parent pulses produced by these processes are normally mutually incoherent because their carrier-envelope-offset (CEO) frequencies are all different combinations of those of the pump (p), signal (s) and idler (i) pulses. Previously, we demonstrated coherent pulse synthesis between SHG pulses from an OPO and those of its Ti:sapphire pump laser by locking the CEO frequencies of both sources to a common value [1]. Here we describe how by locking the CEO frequencies to 0 Hz, broadband phase coherence between a pump laser and multiple outputs from an OPO, spanning > 0.6 PHz in bandwidth, can be achieved [2].

© 2013 IEEE