Coherent beam combination using self-phase locked stimulated Brillouin scattering phase conjugate mirrors with a rotating wedge for high power laser generation

Abstract

The self-phase locking of a stimulated Brillouin scattering-phase conjugate mirror (SBS-PCM) allows a simple and scalable coherent beam combination of existing lasers. We propose a simple optical system composed of a rotating wedge and a concave mirror to overcome the power limit of the SBS-PCM. Its phase locking ability and the usefulness on the beam-combination laser are demonstrated experimentally. A four-beam combination is demonstrated using this SBS-PCM scheme. The relative phases between the beams were measured to be less than λ/24.7.

Output characteristics of high-power stimulated Brillouin scattering pulse compression enhanced by thermal effects based on HT270

“…In the case of the liquid medium, the main issues limiting SBS pulse compression under highrepetition rate operation and high-pump power application are the thermal effects and optical breakdown [26][27][28][29]. The laser absorbed by the medium is converted into heat, causing serious thermal deposition within the medium, an uneven spatial distribution of the medium temperature, significant thermal convection, changes in the medium density gradient, laser-beam deflection, and other phenomena, as shown in Fig.…”

“…The first is the liquid purification method to remove large impurity particles in the liquid medium [ 16 , 28 ] , which can appropriately reduce the total heat absorption generated by the laser absorption within the medium and reduce the optical-breakdown probability. The second category is the method involving flowing liquid and a wedge-based moving focal spot [ 27 , 29 ] , which are used to alleviate the local focusing heat accumulation. However, these methods have only been verified separately through experiments at repetition rates of less than 1 kHz, and there have been few studies on these methods that involved higher repetition rates or systematic research.…”

Stimulated Brillouin Review: Invented 50 Years Ago and Applied Today

“…This should enable the smooth wave front of the initial master oscillator to be created when these beams are combined coherently, because of the self-locking SBS PC mirrors. As of this writing, these researchers are still looking for the most practical beam combiner [19]. The method has an exciting potential, but is quite complex.…”

Developments of Picosecond Lasers Based on Stimulated Brillouin Scattering Pulse Compression

“…Compared with nonlinear crystals for optical parametric amplification (OPA), SBS media, usually are liquids, can provide a much higher limitation on the power loading. Therefore, energy of up to tens of joules can be obtained through the "beam splitting-amplification-beam combination" method [29][30][31]. Additionally, optical limiters, a technique for transmitting a low-intensity beam, made by SBS technology have also been widely used in high-power lasers, which can effectively protect optical elements and improve the stability of the laser system [32,33].…”