Single crystal stacks of ZnSe for high power frequency conversion in the infrared

Periodic stacks of quasi-phase-matched (QPM) nonlinear optical crystals can overcome walk-off and laser damage problems of birefringent crystals used for frequency conversion in the IR: QPM stacks of cubic nonlinear optical III-V semiconductor crystals of the zinc blende structure offer the potential of high average power frequency conversion in the mid IR. We propose a novel bonding technique for fabrication of single crystal stacks of ZnSe layers of a thickness of 1 coherence length each. We have selected ZnSe because it possesses the transparency requirements in the IR, has a very high figure of merit for high power frequency conversion and is transparent in the visible. Interfaces between individual lamellae will have negligible loss without changing the optical properties of the bulk. The process will be applicable to other transparent nonlinear optical crystals, e.g. ZnS, ZnTe, CdS, CdSe for the fabrication of QPM stacks.