Abstract: A radiant energy amplifying device receiving energies from short wavelengths by a plurality of scintillating materials having high quantum yields operating in cascade which are distributed homogeneously in a matrix made of synthetic resinous material whose absorption threshold is at a wavelength less than the absorption zone of the scintillating material located at the beginning of the cascade, wherein the scintillating materials are present in the matrix in a proportion varying according to the material from 2.times. 10.sup.-3 to 10.sup.-7 mole/kg of resin, the highest concentration corresponding to the material being located at the beginning of the cascade.