Sandia Labs FY22 Laboratory Directed Research & Development Annual Report

PROTECTING SENSORS USING PIXELATED OPTICAL SHUTTERS. Sensitive optical detectors are subject to permanent damage when exposed to high-intensity laser light, but this can be mitigated using optical limiters or shutters. With the goal of protecting sensors, this LDRD team designed, fabricated, and developed

two different computation approaches for designing limiter arrays in this platform. Development of one of these computational techniques was led by Sandia Alliance partner University of Illinois at Urbana-Champaign, who used a two-stage neural network to model and optimize sub-wavelength structures capable of thermally efficient optically limiting. (PI: Michael Wood)

high fill-factor, optically triggered optical limiter arrays based on the phase transition in vanadium dioxide (VO 2 ). Techniques for depositing and patterning VO 2 thin films were matured, as well as

(a) Simulated transmission spectrum of the stacked optical shutter element. (b) Angled-view scanning electron micrograph of an etched pixel array. Photoresist (PR) is still intact in the image but was removed before optical testing.

ELECTROMAGNETIC THREAT RESILIENCE VIA A PROTECTIVE FARADAY CAGE. Several key mechanical transduction advancements were made for

University of Colorado Boulder and New Mexico Institute of Mining & Technology, and also leveraged the expertise of a graduate student at Sandia Alliance partner Georgia Tech. Key impacts, which were reported in one publication and six presentations, include providing Sandia space missions with novel architectures for protecting critical assets, enabling capabilities not previously possible for other governmental agencies, and improving robustness for commercial space operations. This project advanced the tools and knowledge base that will empower

electromagnetic (EM) resilience in space systems during this LDRD project, including modeling tools to accurately predict performance of prospective Faraday cages and an optimized design that provided measured shielding effectiveness exceeding 80 dB for frequencies up to 20 GHz. The most compelling accomplishment was demonstration of the threat-hardened autonomous watchdog (THAW) concept, where a protected subsystem was operated through a simulated EM attack strong enough to destroy an

The use of a Faraday cage provides shielding effectiveness to space systems such as satellites when subjected to an EM attack.

exposed antenna and overwhelm unprotected electronics. At various stages of this project, Sandia partnered with National/Regional partners

space system designers to integrate barrier transduction solutions into satellites for increased EM resilience. (PI: Charles Reinke)

57

LABORATORY DIRECTED RESEARCH & DEVELOPMENT