We generated a coherently synthesized optical pulse from two independent mode-locked femtosecond lasers, providing a route to extend the coherent bandwidth available for ultrafast science. The two separate lasers (one centered at 760 nanometers wavelength, the other at 810 nanometers) are tightly synchronized and phase-locked. Coherence between the two lasers is demonstrated via spectral interferometry and second-order field cross-correlation. Measurements reveal a coherently synthesized pulse that has a temporally narrower second-order autocorrelation width and that exhibits a larger amplitude than the individual laser outputs. This work represents a new and flexible approach to the synthesis of coherent light.
Shelton, Robert K.; Ma, Long-Sheng; Kapteyn, Henry C.; Murnane, Margaret M.; Hall, John L.; and Ye, Jun, "Phase-Coherent Optical Pulse Synthesis from Separate Femtosecond Lasers" (2001). Physics Faculty Contributions. 74.