Induced absorption of pump radiation in solutions of organic compounds

The relative quantum efficiency of solutions of 9,10–diphenylanthracene, N–phenylacridone, POPOP, and anthracene was determined as a function of the intensity of pumping with the third (353 nm) and fourth (265 nm) neodymium laser harmonics. The fall of the quantum efficiency with rising pumping intensity was attributed to the appearance of an induced absorption at the pump wavelength.