Two types of solid-state lasers have served as key elements in the development of laser fusion: tunable lasers, such as Ti:sapphire, and lasers with discrete emissions based on neodymium. These lasers have been utilized for research, diagnostics, and as oscillators (i.e., Nd:YLF) in the first stage. Crystal-line phosphates were studied in depth many years ago for laser applications, but these crystals generally fell into disfavor when they could not be easily commercialized. A class of self-activated materials, referred to as stoichiometric phosphates, were particularly interesting, since they could operate efficiently at high active ion concentrations without fluorescence quenching. Neodymium pentaphosphate (NdP5O14) initiated this interest, but the potential for rare-earth orthophosphate (REOP) crystals was not seriously considered at that time. Extrinsic effects observed during some fundamental studies of REOP crystal properties, such as by electron paramagnetic resonance (EPR), may heighten the interest in using these latter materials for far-ranging laser applications, including laser fusion.