Lawrence Livermore National Laboratory



Tommaso Pardini

Overview

This project advanced the state-of-the-art in multilayer interference coatings with custom-tailored properties for national security applications by understanding and overcoming limitations in the physical properties of these coatings. We focused on improving the properties of two major types of multilayers: 1) the reflectance of hard x-ray aperiodic multilayer coatings (MLs), and 2) the laser damage resistance of dielectric multilayer coatings (MLDs).

We developed a new class of hard x-ray MLs for imaging in the 17-59 keV photon energy range for applications including target diagnostics and astrophysics. We elucidated the physical and chemical properties of nanoscale layers of ML materials and their interfaces and developed generalized protocols for aperiodic ML design and deposition. We revealed the origin of important laser damage-prone precursors and the underlying mechanism upon exposure to high-energy and -intensity nanosecond (ns) lasers in the ultra-violet region. In both ML and MLD coatings, we investigated the relationships between deposition conditions and performance. We then applied deposition process modifications specific to each type of ML and MLD coatings to dramatically improve ML reflective performance and MLD laser-damage resistance.

Impact on Mission

Our research leveraged and advanced Lawrence Livermore National Laboratory's core competencies in laser and optical science and technology, advanced materials and manufacturing, high-energy-density science, and space security. We developed an entirely new Laboratory capability for the design and deposition of high-performance, hard x-ray, aperiodic MLs with tailored properties for national security and science applications.The knowledge gained and the capabilities developed can address ignition and stockpile stewardship challenges by helping provide a pathway to higher power and energy on Livermore's National Ignition Facility and other inertial confinement fusion experimental facilities and to higher intensity optics for the Advanced Radiographic Capability and lasers for emerging directed energy systems.

Publications, Presentations, Etc.

Burcklen, C., et al. 2018, "Aperiodic x-ray multilayer interference coatings with high reflectance and large field of view." Proc. SPIE 10691, Advances in Optical Thin Films VI, 106910U. doi: 10.1117/12.2314257. LLNL-PROC-752012.

——— . 2018. "Aperiodic x-ray multilayer interference coatings with high reflectance and large field of view." Advances in Optical Thin Films VI, SPIE Optical Systems Design, Frankfurt, Germany, May 2018. LLNL-PRES-751263.

——— . 2018. "Aperiodic x-ray multilayer interference coatings with high reflectance and large field of view." Physics of X-ray and Neutron Multilayer Structures (PXRNMS) Workshop, Palaiseau, France, November 2018. LLNL-PRES-751263.

——— . 2019. "Depth-graded Mo/Si multilayer coatings for hard x-rays."Optics Express 27(5), 7291-730. doi: 10.1364/OE.27.007291. LLNL-JRNL-760501.

Harthcock, C., et al, 2018. "The impact of voids on laser damage performance of ion beam sputtered hafnia films." SPIE Laser Damage 2018, Boulder, CO, September 2018. LLNL-PRES-758560.

——— . 2019. "The impact and origins of non-stoichiometry on the laser performance of ion beam sputtering deposited hafnia films." SPIE Laser Damage 2019, Boulder, CO, September 2019. LLNL-PRES-791039.

Pardini, T., et al. 2018. "Depth-graded multilayers for broadband imaging applications in the hard x-ray regime."Advances in X-Ray/EUV Optics and Components XIII, SPIE Optics and Photonics, San Diego, CA, August 2018. LLNL-PRES-756550.

Qiu, S., et al. 2017. "Towards understanding the laser performance of hafnia thin film at 355 nm using model systems." SPIE Laser Damage 2017, Boulder, CO, September 2017. LLNL-PRES-738844.

——— . 2018. "The role of interfaces on the laser performance of dielectric coatings under pulsed UV exposure."SPIE Laser Damage 2018, Boulder, CO, September 2018. LLNL-PRES-758548.