In Physics Update for the February 2002 issue of Physics Today ( Physics Today 0031-9228 55 2 2002 9 https://doi.org/10.1063/1.2408449. page 9 ), one item states, “In most dye lasers, the dye concentration cannot go above a millimole/liter without quenching the fluorescence.” Subsequently, lasing at a concentration of 9 mmol/L is highlighted as an achievement by the authors. 1 1. S. Yokoyama, A. Otomo, S. Mashiko, Appl. Phys. Lett. 80, 7 (2002). https://doi.org/10.1063/1.1431400 It should be noted that dye concentrations of several mmol/L, sometimes up to 10 mmol/L, have been known for a long time in the field of laser-pumped dye lasers. 2 2. See, for example, C. H. Chen, J. L. Fox, F. J. Duarte, J. J. Ehrlich, Appl. Opt. 27, 443 (1988). https://doi.org/10.1364/AO.27.000443 REFERENCESSection:ChooseTop of pageREFERENCES <<1. S. Yokoyama, A. Otomo, S. Mashiko, Appl. Phys. Lett. 80, 7 (2002). https://doi.org/10.1063/1.1431400 , Google ScholarCrossref, ISI, CAS2. See, for example, C. H. Chen, J. L. Fox, F. J. Duarte, J. J. Ehrlich, Appl. Opt. 27, 443 (1988). https://doi.org/10.1364/AO.27.000443 , Google ScholarCrossref, CAS© 2002 American Institute of Physics.