Dancing around the necessity of each.
How much fiber do I need in my diet to mitigate bowel cancer, know my gut lining is cleansed regularly from all stagnation that hinders nutrient uptake. Additives, preservatives, inert fillers from medications.
What optics do I need to see clearly and in what environment are they necessary.
How much doping is acceptable, to cope with stress but maintain energy.
Because everyone seems to lean on something.
So let us instead discuss.
E(keV) = 1.2398/λ(μm)
How does a rare earths keV potential or capacity equate to a wavelength
Photonics. Phosphate glass.
Rare earths and value for Fiber power.
Legislation for healthy boundaries of historic endeavors.
Compare the Q values for rare earths from the aforementioned list.
Or refer to the Fuchtbauer–Ladenburg equation, McCumber relation and Excited state absorption, to understand some of the theory behind everything that already exists.
Purcell factor to bridge.
Laser diodes, tungstate’s, the list continues.