Super Broad Non-Hermitian Line Shape from Out-of-Phase and In-Phase Photon-Phonon Dressing in Eu3+: NaYF4 and Eu3+: BiPO4

We report super broad non-Hermitian line shape from out-of-phase and in-phase photon-phonon dressing (quantization) in Eu3+: NaYF4 and Eu3+: BiPO4 nanocrystals. The line shape is controlled by changing time gate position, time gate width, power, temperature, sample, photomultiplier tubes, and laser. We observed that the fluorescence (FL) line-shape contrasts are 69.23% for Eu3+: BiPO4 and 43.75% for Eu3+: NaYF4, owing to the stronger out-of-phase photon-phonon dressing (destructive quantization). Moreover, we observed that the spontaneous four-wave mixing (SFWM) line shape was approximately three times wider at 300 K than at 77 K for the [(12:1)-phase] Eu3+: NaYF4 due to more high-frequency in-phase phonon dressing (strong constructive quantization). Furthermore, we showed that the noise line-shape width remains unchanged for Eu3+: BiPO4 (16 nm) and Eu3+: NaYF4 (12 nm) due to out-of-phase and in-phase photon-phonon dressing balance. Such results have potential applications in multi-channel band stop filter.