High Resolution Broadband Laser Ranging

Broadband Laser Ranging (BLR) is an optical diagnostic that measures the position along the line of sight of surfaces and particle clouds moving at speeds of a few kilometers per second at a repetition rate of approximate to 50 MHz. BLR is a spectral interferometer that uses dispersive Fourier transforms to translate the beat frequency between a reference leg and a signal leg into a surface distance. Current generations of BLR measure position with a resolution of 60 mu m m and use mod-locked 1550 nm fiber lasers with a 20 nm bandwidth. Better position and time resolution is expected from using a broader bandwidth. We present results from a series of tests performed using a new BLR system with a 90 nm bandwidth. We find that our high-resolution BLR system has a measured spatial resolution of 25.1 mu m. LA-UR-19-26850