Large Format Faraday Isolators for High Power Ultrafast Laser Systems

The program addresses a critical need for a key component of an ultra-high optical power isolator that enables the next generation of kilowatt-class ultrafast laser systems to use in many areas of accelerator applications. This program provides this important laser component to realize novel accelerator concepts for future colliders; in the generation, manipulation, and x-ray seeding of electron beams; in the generation of electromagnetic radiation ranging from THz to gamma rays; and in the generation of the neu tron, proton, and light ion beams. With applications demanding ever higher fluxes of particles and radiation, the driving laser technology must also increase in repetition rate-and hence average power-to meet the demand. Presently, no vendor can provide a large aperture isolator with power handling exceeding kW.Objective: The program aims to develop a new generation of free-space optical isolators with significantly higher optical power handling than presently available to reach beyond kW pulse and CW operations.Phase I work: Phase I is targeted to produce a prototype free space isolator capable of 1 kW with transmission exceeding 95% and isolation exceeding 30 dB across the entire 5% bandwidth. A scaled-down functional prototype BIG-based isolator (bismuth substituted rare-earth iron garnet) with an aperture size of 30mm in diameter will be built in Phase I to validate the approach. The unit will be extensively tested at our in-house facility to demonstrate its optical performance and thermomechanical stability. Analysis and plan will be completed that provides a path to extend the design to 100 kW average power operation.Commercial Application: In addition to the scientific communi ty, The proposed next-generation high power optical isolators have direct Application in the high power laser commercial market. The global industrial laser market was over $3 billion last year.