Mutually pumped phase conjugator: ray configuration

We have discovered for mutually pumped phase conjugator (MPPC) with a novel configuration 'ray' in a 0 degree-cut nominally undoped photorefractive BaTiO3 crystal which phase conjugates two mutually incoherent beams simultaneously. Both beams incident +c face of the crystal make a non-zero obtuse angle to the crystal's +c axis, respectively. This leads to an effective mutual coupling as two fans emanating from the input beam shave a large interaction region. This novel MPPC exhibits phase conjugation with three internal reflection sand is remarkably insensitive to angular and lateral positional changes of the two input beams. We refer to this phase conjugator as 'ray of mutually pumped phase conjugator'. The temporal responses, positional and angular acceptance, and the variations of the phase-conjugate reflectively with input beam power ratio have also been determined. These characteristics make this mutually pumped phase conjugator particularly interesting for practical applications such as for injection locking lasers and for optical free space communications.