Colour change of a ruby crystal when irradiated by intense light

This publication has 4 references indexed in Scilit:

• Exfocal Pumping of Optical Masers in Elliptical Mirrors
  Applied Optics, 1964
• Comparison of the absorption spectra of ruby in the ground state and the excited metastable state
  Physics Letters, 1964
• Microwave Inversion Efficiency of Orange Ruby
  Nature, 1963
• Paramagnetic resonance data
  Reports on Progress in Physics, 1959