Synthesis and characterization of new caged dye velocimetry tracers for microgravity droplet diagnostics
1997, American Institute of Aeronautics and Astronautics, Inc. We report three new caged dye Photo-Activated Fluorophore (PAF) probes designed for use with compact interrogation laser sources, such as Nd:YAG and near IR semiconductor diode. Experimental results are presented characterizing key optical and kinetic properties in a variety of alcohol solutions and in water as a function of pH. Of particular interest is a new caged Q-rhodamine PAF which was found to exhibit extremely strong signal levels in both water and alcohol and is well suited to interrogation with the second harmonic of Nd:YAG at 0.532 microns. Stereoscopic images of internal circulation in 1-4 mm diameter methanol droplets were obtained using order 1 mJ laser pulses, which could, potentially, be delivered to a remote apparatus with optical fibers.