Time-resolved spectral response of asymmetrical optical microcavity structures under laser-driven shock compression

Abstract

The time-resolved spectral responses of three asymmetrical optical microcavity (AOMC) structures under laser-driven shock compression were investigated. The objective was to compare the performance of these multilayer structures and explore the potential in dynamic shock “pressure” sensing, given their unique ability to capture spatially heterogeneous pressure distributions across 2D surfaces. Different AOMC structures were fabricated, with amorphous SiO2, amorphous Al2O3, and PMMA cavity layers between deposited silver reflecting layers producing the characteristic spectral features of the structures. An experimental setup employing laser-driven shock compression was used to generate nanosecond scale pressure loads of ∼1-10 GPA, and the corresponding time-resolved spectral response and in-situ particle velocity of the AOMCs was simultaneously recorded. Each of the AOMC multilayers showed clear spectral shifts as a function of pressure with nanosecond level correlation to the independently measured velocimetry data. These results indicate that the time-resolved physical state of the cavity layer drives the spectral response of the optical microcavity structures. The results also validate qualitative predictions of the multilayer structures’ response to dynamic compressive loads and their potential for use in time-resolved sensing of pressure.