Modification of the upconversion spontaneous emission in photonic crystals

Influence of competition between excited-state absorption and spontaneous emission from intermediate excited state on upconversion emission was investigated firstly in photonic crystals. The result clearly shows that upconversion emission can be modulated by the photonic crystal. When upconversion emission band from intermediate excited state overlaps with the photonic band gap, short wavelength unconversion emission from upper state is obviously enhanced due to an inhibition of spontaneous emission from the intermediate excited state in the photonic crystal. We believe that the present work will be valuable for not only the foundational study of upconversion emission modification but also new optical devices in upconversion displays and short wavelength upconversion lasers.