Perspex® Helios Yellow
Lack of peaks under longer wavelengths suggests this sample relies heavily on fluorescence alone.
It may be possible to get laser action out of it by pumping with a BDR-209.
I have noticed a pattern emerging across the samples however. I am convinced that they all must have the same dye or the same two dyes present in differing concentrations. The green and yellow/orange bands are pretty consistent just vary in intensity depending on what part of the spectrum they favour.
Relative Intensity Spectrums
Conclusion:
Helios Yellow has two strong peaks at 548-549nm and 582-586nm. This sample is biased towards shorter wavelengths with 406nm being optimal and 486nm following. Another weak band can be produced at 527-535nm if using 522/532nm. However pumping at these wavelengths is unlikely to be sufficient enough to reach lasing threshold. 589nm and 653nm produced very weak results overall. Not unsurprising when this sample favours more energetic florescence and therefore higher energy photons in shorter end of the spectrum. This could be a good alternative sample to produce yellow light, however its main emphasis especially when pumped by 406nm is lime-green emission.