Wave-front dividing beam combined laser fusion driver using stimulated Brillouin scattering phase conjugation mirrors

Abstract

The beam combination method using stimulated Brillouin scattering phase conjugation mirrors (SBS-PCMs) is a promising technique for a commercial laser fusion driver operated with a high repetition rate around 10 Hz. The phase control of the SBS wave is essential for realization of the coherent beam combined output in the beam combination. For this reason, we proposed the ‘self-phase control technique’ of the stimulated Brillouin scattering wave, and its principle has been demonstrated experimentally over the past several years. In this work, the experiments are performed for the phase stabilization of wave-front dividing two-beam and four-beam combined systems by reducing the beam pointing fluctuation of the laser source using a beam expansion.

Conceptual design of the Kumgang laser: a high-power coherent beam combination laser using SC-SBS-PCMs towards a Dream laser

“…Since then, the results have improved and the method has been applied to four-beam coherent combination lasers with both the wavefront dividing method and the amplitude dividing method [23][24][25][26][27][28][29][30][31] . Figure 5 shows the experimental setup for verifying the principles of the SC-SBS-PCM [24] .…”

“…The standard deviation of the measured phase fluctuation is λ/35.7. Figure 7 shows the experimental setup for controlling the phase of the SC-SBS-PCM [29] . In this case, a two-beam aperture with a beam diameter of 8 mm is used.…”

The Current Trends in SBS and phase conjugation

“…Four Beam Combination Laser Amplifier -Wavefront Dividing Scheme. A four-beam combined laser with the wavefront dividing scheme was successfully demonstrated both with and without amplifiers (Kong et al, 2009b;Shin et al, 2010b). Figure 15 shows the experimental setup of the four-beam combined laser with the wavefront dividing scheme.…”

Current status of the development of the Kumgang laser

“…Furthermore, the phase-conjugation property of the SBS-PCM prevents the degradation of the amplified beam quality [2]. Therefore, coherent beam combination lasers using SBS-PCMs have been studied for more than a decade, with the feasibility of these systems experimentally proved by Kong et al [3][4][5][6][7].…”