Phase-Coherent Optical Pulse Synthesis from Separate Femtosecond Lasers

TLDR

We generated a coherently synthesized optical pulse from two independent mode‑locked femtosecond lasers, extending the coherent bandwidth available for ultrafast science. The two lasers, centered at 760 nm and 810 nm, were tightly synchronized and phase‑locked, with coherence verified by spectral interferometry and second‑order field cross‑correlation. The synthesized pulse exhibited a narrower second‑order autocorrelation width and higher amplitude than the individual lasers, demonstrating a new flexible approach to coherent light synthesis.

Abstract

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.