Interference coatings for high energy and average power femtosecondclass lasers in the 0.8-2um wavelength range

The problem/situation that is being addressed concerns the development of ultrafast coatings that will meet the specifications of the DoE solicitation: “broad-bandwidth, laser damage threshold of 0.5 J/cm2 (1 ps), engineered using a process that is scalable to large areas.” A major bottleneck in achieving prolonged reliable operation of ultra-high intensity lasers at high repetition rate is the failure of optical component in the laser chain, especially during and post-compression stages. Among the optical components, the weakest link has been identified to be pulse compression gratings, and to a lesser extent, high reflector mirrors and antireflection coatings exposed to the highest intensities. How we propose to address the problem/ situation: In Phase I and II of our project, a comprehensive computational infrastructure was built that incorporates proper Keldysh field ionization, collision, plasma, and propagation effects to create a dynamic 2D finite difference time domain (FDTD), and into a 3D particle-in-cell (PIC) framework model that reliably allows us to simulate high intensity laser interaction with multi-layer dielectric (MLD) systems. Using this comprehensive computational infrastructure, the proposed Phase IIA will have two main focuses: (1) the development of multilayer dielectric (MLD) high reflector and antireflection interference coatings for high repetition rate multi-tera-Watt and peta-Watt class lasers; and (2) the development of MLD gratings with optimized efficiency, bandwidth and high laser damage threshold for the most promising 1 ?m and 2 ?m platforms for a Type II laser. Novel high bandgap material mixtures and coatings’ geometries will be designed and fabricated, laser damage tested and characterized ex situ to identify failure mechanisms and to implement strategies to mitigate them. Commercial applications and other benefits. Interference coatings demonstrate a solid performance for low-fluence narrow-bandwidth lasers but fail dramatically when tested with ultrashort pulses and at high repetition rate. This challenge coupled with a scarce supplier market open enticing commercial opportunities. Ultrafast coatings with superior laser damage performance will advance the engineering of high average and peak power femtosecond lasers for next-generation accelerator-type applications. If realized, they can create a $50 million/year, high power-million to billion shot optics market for laser-based accelerators in scientific and medical markets.