Achieving the optimum velocity resolution of coherent rayleigh-brillouin scattering

Single shot coherent Rayleigh-Brillouin scattering (CRBS) is demonstrated to acquire gas flow velocimetry measurements in acquisition times on the order of a few hundred nanoseconds. When applying single-shot CRBS velocimetry in gas flows, it is essential to understand the theoretically best achievable velocity resolution. In single shot CRBS a spectral shift of the order of 10 MHz is translated into a detectable temporal shift of 0.1 nanoseconds. Based on this, we demonstrate here that for typical operating parameters, a velocity resolution as low as 0.5 m·s⁻¹ can be obtained experimentally. By precisely tailoring the chirp rate, a quick adjustment of the velocity resolution of single shot CRBS can be achieved, which can then be tuned accordingly for different experimental conditions.