We propose to analyze, fabricate, and test a new class of external resonators containing volume- holographic output mirrors for establishing coherence across two-dimensional diode laser arrays. The resonators are expected to have many new properties that will enhance the performance of coherent diode laser arrays. We will perform an analysis of the lateral modes and modal discrimination of this new resonator geometry. Good discrimination properties are imperative for high-power operation of diode laser arrays without coherence degradation. We will also study edge effects and resonator optimization by computer models. Volume-holographic elements will be fabricated to match the desired lateral mode from a given diode laser array. The multi-step process consists of using lens design software to calculate the required recording wavefront, fabricating a computer-designed diffractive element by e-beam lithography and dry etching, and using the diffractive element to expose a volume holographic material. The performance of the volume- holographic resonator will be studied with a linear diode laser array. We expect this new type to resonator geometry to have significant advantages in lateral mode control, efficiency, size, and high- power operation. Small cavity lengths may permit future integration into a two-dimensional monolithic structure. In addition, the basic technology developed in this proposal can be applied to many other electrooptical systems such as frequency doublers, solid-state lasers, and complex illuminators.
