Measured fluorescence from single-particle clusters of dye-doped polystyrene microspheres, dried nonspherical particles of tryptophan, and single polystyrene microspheres is enhanced in the backward direction (180° from the incident laser). This enhancement (a factor of 2–3 compared to 90°), which can be interpreted as a consequence of the reciprocity principle, increases with the particle refractive index.
© 2002 Optical Society of America
Yong-Le Pan, Steven C. Hill, Jean-Pierre Wolf, Stephen Holler, Richard K. Chang, and Jerold R. Bottiger, "Backward-Enhanced Fluorescence from Clusters of Microspheres and Particles of Tryptophan," Appl. Opt. 41, 2994-2999 (2002)