Publications Details

Time-stretched photonic Doppler velocimetry

Mance, J.G.; La Lone, B.M.; Dolan, D.H.; Payne, S.L.; Ramsey, D.L.; Veeser, L.R.

Inertial confinement fusion facilities generate implosions at speeds greater than 100 km/s, and measuring the material velocities is important and challenging. We have developed a new velocimetry technique that uses time-stretched spectral interferometry to increase the measurable velocity range normally limited by the detector bandwidth. In this approach, the signal is encoded on a chirped laser pulse that is stretched in time to reduce the beat frequency before detection. We demonstrate the technique on an imploding liner experiment at the Sandia National Laboratories’ Z machine, where beat frequencies in excess of 50 GHz were measured with 20 GHz bandwidth detection.