Nonlinear Photoresponse of Nayf4:Yb,Er@Nayf4nanocrystals Under Green Cw Excitation: A Comprehensive Study Publisher



Ghazyani N^{1, 2} ; Majles Ara MH^{1, 2} ; Raoufi M^{3, 4} Show Affiliations
Source: RSC Advances Published:2020

Abstract

One of the efficient and well-known upconverting nanomaterials is NaYF4:Yb,Er@NaYF4, which emits photoluminescence at 545 nm and 660 nm under an excitation of 980 nm. Here, the nonlinearity of β-NaYF4:Yb,Er@NaYF4 at 532 nm is investigated using three nonlinear approaches. For the first time, the nonlinear optical conjugation of NaYF4:Yb,Er@NaYF4 nanocrystals is observed using the degenerate four-wave mixing method. In the optical bistability study, the optical hysteresis of NaYF4:Yb,Er@NaYF4 is measured using the Mach-Zehnder interferometer nonlinear ring cavity, and the results of bistability loops show different behaviors at different power regimes. Finally, the Z-scan technique is used for determining the nonlinear absorption and refraction coefficients, which are calculated in the order of 10-4 (cm W-1) and 10-8 (cm2 W-1), respectively. The results indicate that by increasing incident powers, optical behaviour changes in both optical bistability and Z-scan. Therefore, the results exhibit that the β-NaYF4:Yb,Er@NaYF4 nanocrystals have nonlinear photoresponses at both 980 and 532 nm, which could be promising for photonic devices based on NIR light and visible light. © The Royal Society of Chemistry.