Coherent combination of ultrashort pulse beams using two diffractive optics

Abstract

A novel coherent beam combiner, capable of combining large numbers of femtosecond pulse beams using two diffractive optics, is presented. The diffractive optic pair cancels pulse front tilt, while uncorrected dispersions are minimized. An example using four beams is modeled numerically and tested experimentally, demonstrating 120 fs pulses combined without degradation of pulse width. Scaling the concept, we show analytically that combining loss due to uncorrected dispersions is only a few percent for ∼200 beams with 130 fs pulses.