High-speed turbulent flows are marked by rapid fluctuations in velocity and thermodynamic properties. While many laser based methods (e.g. PIV, PLIF, etc.) exist to interrogate these properties, the repetition rate is often limited to order of 10-100 Hz. In this work, a 3rd generation MHz rate pulse burst laser system was designed and constructed. The system is capable of producing high energy laser pulses at repetition rates exceeding 1 MHz. The 3rd generation system incorporates two distinct design changes that distinguish it from earlier generation systems. The first is that pulse slicing is now achieved using an economical acousto-optic modulator (AOM) and the second is the use of a variable pulse duration flashlamp driver which provides relatively uniform gain over a ~700 µsec window. The use of an AOM for pulse slicing enables flexible operation such as pulse-on-demand operation with variable pulse durations ranging from 10 nsec to DC.
Diagram of Auburn University 3rd-generation Pulse Burst Laser system, configured for output at 532 nm.
Photograph of the MHz rate pulse burst laser system
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