Volume Phase Diffractive Optical Elements for Laser Cavities

ABSTRACT:ANTEOS, Inc proposes to develop an innovative technology for holographic recording of relief-free Volume Phase Diffractive Optical Elements (VPDOE) for high power laser systems, including laser cavity optics for VECSELs, based on ZnSe semiconductor material, which is well transparent from the visible to long-wave infrared wavelengths between 480 nm and 14 microns. A proprietary process of photo-modification irreversibly changing refractive index of the semiconductor material under illumination with low intensity light is used for direct optical recording of the relief-free VPDOE structure at room temperature. Because no foreign material is introduced during processing of the semiconductor, the fabricated VPDOEs should exhibit high temperature stability as well as resistance to laser damage and harsh environment. In Phase I of the project, we will prove feasibility of the proposed concept by optical recording of model relief-free VPDOEs, demonstrating their beam focusing performance, and temperature stability. In Phase II, the prototype VPDOEs for MWIR laser cavities will be fabricated, tested, optimized and delivered to DoD for implementation in its missions. BENEFIT:One-step optical recording is less labor intensive than traditional grinding, polishing or etching and offers considerable cost reduction due to saving the expensive ZnSe material. This creates strong competitive advantage for commercialization of the developed technology. In addition to immediate military applications of the VPDOEs in laser cavities for infrared countermeasures, remote sensing and monitoring, target detection and ranging, free space optical communication, detection of chemicals, the proposed relief-free diffractive optics having improved performance, high resistance to laser damage and harsh environments will find many industrial, scientific and medical applications, including spectral devices and detectors, chemical spectroscopy, industrial process and material quality control, environmental monitoring, trace gas identification and analysis, semiconductor lasers and telecom semiconductor devices, optical memory and laser mode tuning, material laser processing and medical surgery.