Integrated multiphysics design of high-power short-pulse lasers

Rapid ordersofmagnitude improvement in the average power of highintensity lasers with ultra short pulse lengths has become central to the continued advancement of compact, highgradient particle accelerators for electrons and positrons. There is currently a lack of broadly available modeling software to selfconsistently capture the required physics of gain, thermal loading and lensing, spectral shaping, and other effects required to quantitatively design such lasers. The first objective is to validate new computational models from Phase 1 via comparison with experimental data in a parameter regime relevant to kHz repetition rate, kWscale average power Ti:sapphire laser amplifiers. The second objective is to demonstrate correct integrated modeling of a 100 TW peak power amplifier via comparison with experimental measurements. The third objective is to develop a browserbased GUI suitable for use by the laser design community, to be built on easytouse, open source software. During Phase 1, new algorithms were developed and implemented in software to model laser wavefronts propagating through Ti:sapphire crystals, including aspects of amplification and thermal effects. A novel operator splitting approach has been developed, where both the stretched laser pulse and the crystal are sliced in a manner that enables robust algorithms, accuracy and interactive solutions. Full Fourier optics of the laser pulse is included, using a novel theoretical treatment of wavefront propagation that leverages an open source physical optics code. Thermal modeling of a cylindrical Ti:sapphire crystal has been demonstrated, using a parallel open source differential equation solver. A prototype online graphical user interface has been developed, leveraging an open source framework for scientific cloud computing. The Phase 1 algorithms and software will be generalized to include linear canonical transforms based on arbitrary optical transport matrices, and to include nonlinear effects in the index of refraction and the gain within a Ti:sapphire crystal that has been pumped with realistic asymmetries. The laser pulse model will be generalized to include finite bandwidth effects. The thermal properties of Ti:sapphire crystals will be further simulated, including mechanical stress. Experimental measurements at a stateoftheart laserplasma facility will be used to validate the software. The cloudbased graphical user interface will be completed and made available. The software developed for this project will be open source, and novel aspects of the software design will be published in the scientific literature. The cloud computing approach is uniquely powerful. New users are up and running in minutes and can share simulations instantaneously. Subscriptionbased sales and associated consulting will generate significant revenue.