Abstract

BaTiO₃ crystal is self-pumped by coherent beams A₁ and A₂ from a multilongitudinal-mode Ar⁺ laser. The self-pumped $A_1^{*}\text{ and }{A}_2^{*}$ with a 4800-Å laser showed oscillations whose frequency increases with laser intensity. They are bistable and do not coexist. With 5145 and 4765 Å, $A_1^{*}\text{ and }{A}_2^{*}$ coexist and are stable with minor coherent pulsations. When coexisting, $A_2^{*}\text{ and }{A}_1^{*}$ are strong with a 5145-Å laser while they are very weak with 4765 Å. A mutually consistent fanning occurs so that a component of each fanned beam (A₁ and A₂) is incident on the other beam’s grating at the correct Bragg angle to undergo total internal reflection and get into the reverse direction of the other. Thus when A₁ is shut off the detector D₂ of $A_2^{*}$ shows a sharp intensity drop and similarly the D₁ of $A_1^{*}$, when A₂ is off. The counterparts of the images at D₁ and D₂ are seen outside the crystal between the outgoing directions of A₁ and A₂. When the beams A₁, and A₂ with 5145 Å are incoherent, the sequence A₁ + A₂ does not commute with A₂ + A₁.

© 1987 Optical Society of America