Development of a Tunable Megahertz Pulse-burst Alexandrite Laser System
A new frequency-tunable pulse-burst alexandrite laser operating in the megahertz range has been built at Princeton University to enable time-accurate LIF and Filtered Rayleigh diagnostics of rapidly changing fluid and combustion processes. Our long term objective has been to extend our high-speed laser imaging capability to the imaging of individual molecular species such as NO and OH in high-speed and unsteady flows. In this regard, our efforts have been guided by the experience gained with a megahertz rate Nd:YAG pulse-burst system built previously by Wu et al. [l]. The present Alexandrite system operates in the vicinity of 761-nm but, in the future, will be injection-tunable over a 10 nm range. Also at a later date, frequency upconversion crystals will be added to produce tunable UV light in the vicinity of 254-nm for use with atomic mercury vapor filters. To date, the power output per pulse has been limited, requiring design changes. 2003 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved.