Single Crystal Stacks of ZnSe for High Power Frequency Conversion in the Infrared

Period of Performance: 07/17/1998 - 07/17/2000


Phase 2 SBIR

Recipient Firm

Onyx Optics, Inc.
6551 Sierra Lane
Dublin, CA 94568
Principal Investigator

Research Topics


Phase matching for frequency conversion can be achieved with cubic crystals with high nonlinear optical coefficients, high damage thresholds and wide regions of optical transparency by using a periodic arrangement of thin plates of the crystals oriented such that the sign of the nonlinearly reverses from plate to plate. There are no beam walk-off problems for QPM stack devices, in contrast to birefringent crystals for frequency conversion. In practice, it has proved difficult to produce a large number of lamellae of correct thickness, orientation and optical quality for operational devices. We have demonstrated technical feasibility of the principle of a novel bonding technique of individual lamellae for the fabrication of ZnSe QPM stacks which affords the control required for producing stacks of 50 to 100 layers. Features of the process include interfaces of 0.1% transmission loss at 2 micron without altering the nonlinear optical properties of the bulk. We have established procedures to monitor process variables during and after completion of the stacks. The process will also be applicable to other nonlinear optical semiconductor crystals, e.g. GaAs, GaP, GaSb, InP, ZnS, ZnTe and CdTe. The proposed process development will result in QPM crystal stacks for high average and low power second harmonic generation and optical parametric oscillators for the mid IR.