Development of a Multidimensional, Holographic Velocity Interferometer System

Project Overview

Optical probing of dynamically-driven experiments using two-dimensional velocity interferometer systems (VISARs) employs coherent laser illumination to record images with high time resolution. Data from single-shot events of time duration ranging from nanoseconds to microseconds are recorded as intensity images on array detectors. While the velocity interferometer provides Doppler shift information, the optical phase of the imaging beam is not known. There are many situations where more information could be gained if the optical phase in the imaging beam were known. To avoid the complexities of standard approaches to obtain optical phase (holography or interferometry) we explored the use of a much simpler setup, a multi-plane recording, combined with iterative phase retrieval algorithms. We constructed two benchtop setups, including one with a two-dimensional VISAR system, and collected a series of data sets to test and develop the phase-retrieval algorithms. The results show that these methods show great promise for providing phase information that can be used to supplement current two-dimensional velocimetry diagnostics and will provide novel capabilities for measuring both position and velocity of materials and objects driven by dynamic processes.

Mission Impact

The facility-scale diagnostic that we envision is compatible with existing VISAR implementations already fielded at high energy density (HED) science facilities, such as NIF, Z, and OMEGA. This capability has broad application in the general field of HED sciences, including the inertial-confinement-fusion program and the stockpile-stewardship program. Accordingly, the project can have direct impact on many of the missions associated with these facilities.

Publications, Presentations, and Patents

Celliers, P. M. and D. J. Erskine. "Velocity and Position Measurement of Optical Reflectors in a Three-Dimensional Volume." LLNL Record of Invention IL-13649.

Celliers, P. M., et al. "Extending Imaging VISARs into 3D with Digital Holography and Phase Retrieval." Presentation, American Physical Society Topical Group on Shock Compression of Condensed Matter, Anaheim, CA. July 2022.

Davies, E. J., et al. "Toward a 3D Velocity Interferometer Testbed: Concept and Algorithm Exploration." Presentation, Digital Holography and Three-Dimensional Imaging, OSA. Virtual. July 2021.

Erskine, D. J., et al. "Toward a 3D Velocity Interferometer Testbed: Early Results." Presentation, Digital Holography and Three-Dimensional Imaging. OSA. Virtual. July 2021.

Hutchinson, T. M., et al. "Development of a Two-Frame Holographic Imager for Shock Physics Research." Presentation, American Physical Society Topical Group on Shock Compression of Condensed Matter, Anaheim, CA. July 2022.