Fundamental limits of time-resolved velocimetry

Abstract

Time-resolved velocimetry is a core diagnostic in dynamic compression experiments. These diagnostics map hundred THz optical frequencies, which cannot be measured directly, to a recordable signal phase, frequency, or amplitude. All three mappings have benefits and shortcomings, but the fundamental limits of each share several features. Velocity uncertainty is always proportional to wavelength and noise fraction, while the role of characteristic time scale depends on the encoding mechanism. This relationship determines the suitability for a particular diagnostic at short and long time scales.