Development of a Photonic Doppler Velocimetry Diagnostic Operating at 830 nm

Abstract Photonic Doppler Velocimetry, originally developed at 1550 nm, has become over the past decades a standard diagnostic for studying material response to dynamic loading or for studying clouds of ejecta. However, it is known that its velocity resolution cannot be increased along with its temporal resolution. To go beyond these limitations, Photonic Doppler Velocimetry systems operating at shorter wavelengths can provide better velocity measurements. In this study, we report about a new Photonic Doppler Velocimetry system operating at 830 nm, which is considered to be the best trade-off between optical losses, time resolution and velocity resolution for systems operating at lower wavelengths. To evaluate the benefits of this new diagnostic, and compare it directly to conventional 1550 nm Photon Doppler Velocimetry, laser-driven shock wave experiments were conducted simultaneously with both diagnostics on aluminum and stainless steel samples. Reference shots were also performed with VISAR measurements at 532 nm, while 1D hydrodynamic simulations were used to interpret the response of materials to shock loading. As a result, the 830 nm operating system reveals a significant enhancement on the temporal and velocity resolutions, making it particularly well suited for the study of the dynamic behaviour of materials under very high strain rates.