A new method of analysis of high power phase conjugation

The phase conjugate nature of the geometric optics component of stimulated Brillouin scattering (SBS) is demonstrated by using the Luneberg-Kline asymptotic series. First, the preference for geometric optical ray retracing is established for the case where the process is dominated by acoustic loss. This is not necessarily the same as phase conjugation. It is then demonstrated that the spatial variation of the slowly varying part of the phase of the zero order, geometric optics component of the backscattered wave reproduces that of the incident wave. Thus, the geometric optics component of the backscattered wave is the phase conjugate of the incident wave. The transport equations for the higher-order terms are derived and serve as a starting point for the investigation of the causes of phase conjugation fidelity degradation