Four-beam Coherent Combination by Using Stimulated Brillouin Scattering with Wavefront Division

Abstract

Using stimulated Brillouin scattering phase conjugate mirrors (SBS-PCMs), we conducted a coherent beam combination of wavefront-divided beams. "Self-phase-controlled" SBS-PCMs were used to lock and control the phases of the SBS wave. Using an interferometer, we monitored the relative phase differences of the four spatially divided beams in real time. With long-term phase stabilization, the phase differences between the reference beam and the other three beams were well stabilized at standard deviations of lambda/36.3, lambda/35.8, and lambda/43.4 for a duration of 2500 shots (250 s).