Modulation of upconversion white light emission in PMMA/NaYF(4):Yb(3+), Er(3+), Tm(3+) composite photonic crystals

In recent years, spontaneous emission modulation of emitters in photonic crystals (PCs) has been widely reported. However, the modulation of PCs on upconversion (UC) white light emission has been rarely studied. In this Letter, triply doped PMMA/NaYF(4):Yb(3+), Er(3+), Tm(3+) composite photonic crystals were successfully fabricated and white light emission was obtained. It is interesting to observe that the chromaticity could be conveniently tuned by changing the photonic stop band (PSB), the incident angle, or the power of the excitation light.