Abstract

A poled BaTiO₃ crystal (8×8×6 mm³) is pumped by mutually coherent beams A₁ and A₂ in horizontal polarization from a multilongitudinal mode Ar⁺ laser (4765 Å). The angle between A₁ and A₂ is 40°, while A₂ makes ~25° with the c axis in the horizontal. The self-pumped phase-conjugate beams A₁ and A₂ are steady under individual pumping when the beams enter the crystal through the center of the face.¹ If the point of entry is ~1.5 mm from the edge nearest to A₂, A₂ shows systematic oscillations whose frequency increases with laser wavelength and power, while A₁ continues to be steady. If both beams pump simultaneously the detectors D₁ and D₂ of A₁ and A₂ show about sixteenfold increase in intensities with coherent but irregular pulsations. This is because of the mutual fanning of A₁, and A₂, which leads to their Bragg diffraction^1,2 into the reverse directions of each other to D₂ and D₁, respectively.

© 1988 Optical Society of America