Tunable pulse-burst laser system for high-speed imaging diagnostics

1998 by Princeton University. The pulse-burst Nd:YAG laser has recently been developed and demonstrated as a useful tool for capturing very high-speed dynamic processes in fluid flows. Images have been taken at up to 1 million frames per second using this laser, together with a new MHz-rate CCD camera. The work reported here seeks to extend the pulse-burst laser technology both to make the laser tunable and to enable it to operate at higher power. Tunability is important over a narrow frequency range in order to utilize the laser for Filtered Rayleigh Scattering, and over a broad frequency range for applications such as laserinduced fluorescence. A first step along this path is to use a seeded diode laser as the initial master oscillator. The diode itself gives short pulses, which lead to higher power output and better frequency doubling. By seeding the diode laser, its frequency can be controlled and its output tuned for Filtered Rayleigh Scattering applications. Seeding forces the laser to operate in a single mode, so the output is free of temporal fluctuations associated with mode beating. Seeding is also critical to the pulse amplification. The second step is to use the output from the pulse-burst laser to pump a dye or Ti: Sapphire laser to realize broad frequency tunability. Preliminary experimental results of the pulse-burst pumped dye laser are presented in this paper.

Tunable pulse-burst laser system for high-speed imaging diagnostics Conference Paper